* Chemical Rage will rarely save Alchemist against Ursa's Fury Swipes.
* Enrage allows Ursa to both be a threat to Alchemist and avoid his over time damage.

* Timbersaw's physical survivability revolves around Reactive Armor, which is largely ignored by Fury Swipes due to the extreme amounts of damage it does in a very few number of attacks.
* Timbersaw's burst damage will not do much against Enrage, although he could easily use Timber Chain to escape, wasting the duration of it.

* Skywrath Mage can easily harass Alchemist in the laning phase with multiple Arcane Bolts. Additionally, if Alchemist is in the process of throwing an Unstable Concoction, and has no way to dispel Ancient Seal, the self stun becomes an easy set up for Mystic Flare.
* Caution, however, as a decently farmed Alchemist with {Item ID:Radiance} and {Item ID:Manta Style} can easily send illusions to harass and force Skywrath Mage out.

* Magical burst damage is Timbersaw's weakness, and Ancient Seal not only amplifies it but also prevents him from using Timber Chain to escape for up to 6 seconds.
* He generally doesn't build early items to deal with silences.
* Reactive Armor does not trigger on magic damage or spells, meaning that even a Pipe of Insight won't give him the massive sustain he normally gets from attacks.
Additional:
* Skywrath Mage's long range and low cooldown magic damage spells can easily harass Timbersaw out of lane.
* Ancient Seal is not only a long lasting silence, (one of Timbersaw's biggest weaknesses) but it also makes him even more vulnerable to magical burst damage.

* Ember's magic damage build is able to burst down Alchemist due to his low strength gain and Alchemist's normal item pick up.

* Searing Chains prevents usage of Timber Chain.
* Timbersaw is vulnerable to magical burst damage, which Ember Spirit provides with Fire Remnant and Flame Guard.
* Timbersaw's abilities deal pure damage, thus they cannot remove Flame Guard.

* Quas-Exort Invoker can win the mid lane easily against Alchemist because Quas regeneration will nullify Acid Spray's damage over time and Exort damage bonus will allow Invoker to out last hit Alchemist.

* Cold Snap can prevent Timbersaw from using both Timber Chain and Chakram due to the frequent stuns interrupting the lengthy cast animations, as well as stopping him mid-chain. This can negate Timbersaw's attempts to escape or dole out extra ability damage.
* Later in the game, Invoker's heavy magical and pure damage can be difficult to avoid, meaning Timbersaw's armor is less useful.

* Reaper's Scythe can kill Alchemist before Chemical Rage has the time to heal him.
* Ghost Shroud can prevent Alchemist from attacking Necrophos, as well as make him immune to Acid Spray and Unstable Concoction damage.
* Heartstopper Aura will do damage as long as Necrophos is alive based on health percentage, which is a problem for a strength hero such as Alchemist.

* Heroes that have escape abilities (such as Queen of Pain, Storm Spirit or Timbersaw) can be either nullified by Reaper's Scythe or a complimentary item for Necrophos (like Rod of Atos or Scythe of Vyse). If Necrophos is quick enough and enters range, they can quickly, if not instantly, die if they are not quick enough.

Additional:
* Heartstopper Aura effectively negates Timbersaw's large HP pool as well as HP regen.
* Death Pulse together with health and mana regeneration from killed creeps helps Necrophos and his teammates survive Timbersaw's burst damage.
* As a tanky hero that stays in the middle of teamfights, Timbersaw is an easy target for Reaper's Scythe.

* Ice Blast cancels out Chemical Rage's rapid health regeneration. It can also take advantage of Alchemist's Armlet of Mordiggian toggling, as it will make HP drain insanely fast, essentially killing the bearer in no time.
Additional:
* Ice Blast nullifies the health regeneration granted by Chemical Rage, which Alchemist greatly relies on to stay alive in battle.
* Alchemist tends to build Armlet of Mordiggian which can be deadly during Ice Blast.

* Heroes that withstand damage like Timbersaw, Bristleback, Dragon Knight and others will have their durability largely reduced when hit by an Ice Blast due to the risk of shattering.

* Viper can bully Alchemist out of mid lane quite easily, forcing him to either retreat into jungle, or stay harassed in lane, and get very few last hits. Vipers break also completely disables Greevil's greed which prevents Alchemist to earn his amazing amounts of money.

* Nethertoxin prevents Timbersaw from gaining stacks on Reactive Armor.

* Heroes who rely on skills to become a heavy hitter in a certain amount of time can waste their timing because of a lucky Lucky Shot's disarm: Terrorblade, Sven, Clinkz, Windranger, Alchemist, Dragon Knight, Legion Commander

* Rolling Thunder's stuns make it harder for Timbersaw to escape with Timber Chain.

* Pugna's Decrepify makes sure that either Alchemist is unable to hit anyone while also being slowed and susceptible to magical damage, or can protect an ally from physical attacks. Besides, Pugna can push early on, when Alchemist is not strong enough to repel it, so by the time Alchemist comes online, he might be forced to sit in base.

* Nether Ward can punish Timbersaw, as Timbersaw is a spell-caster with low cooldowns. Furthermore, Timbersaw usually appears in the midst of battle, placing himself in range of Nether Ward's Mana Flares.
* Timbersaw has no stuns or silences to stop Life Drain. Since all of Pugna's Spells are magical, the damage can be devastating to Timbersaw.
* Decrepify can further increase all the magical damage done to Timbersaw, bypassing the enhanced physical resistance he can get from Reactive Armor.
Additional:
* Nether Ward can punish Timbersaw, as Timbersaw is a spell-caster with low cooldowns. Furthermore, Timbersaw usually appears in the midst of battle, placing himself in range of Nether Ward's Mana Flares.
* Timbersaw has no stuns or silences to stop Life Drain. Since all of Pugna's Spells are magical, the damage can be devastating to Timbersaw, especially when combined with Decrepify

* Heroes who are melee but cannot fight back against Eclipse will really struggle with Luna: Monkey King, Alchemist, Timbersaw.

* Heroes who are melee but cannot fight back against Eclipse will really struggle with Luna: Monkey King, Alchemist, Timbersaw.

* Melee heroes that get kited easily have hard times dealing with Puck without any lockdowns, as Puck is one of the most mobile heroes. Heroes like Sven, Lifestealer, Ursa and Alchemist may have problems to get to Puck without proper initiation items. They also lack reliable lockdowns, as their disables are easily avoidable for Puck, or are just a soft disable.

* Any Hero with high mobility will be neutralized by dream coil: Queen of Pain, Storm Spirit, Ember Spirit, Lycan, Bloodseeker, Anti-Mage, Timbersaw

* Because Timbersaw relies heavily on his spells to deal damage, Silence can easily disable him in a team fight.
* Exorcism's spirits do not count as regular attacks, and will not add stacks of Reactive Armor.

* Timbersaw is heavily reliant on his abilities for damage and escape, allowing Silencer to effectively disable him and make him useless in both team fights and 1v1 scenarios.
Additional:
* Arcane Curse deals repeated stacks of damage to Timbersaw because he relies on constantly using his abilities.
* Glaives of Wisdom deals pure damage and when cast manually, nearby creeps will not attack silencer, making it an effective harassment tool.
* Although Last Word takes a while to trigger, it will break Timbersaw's ability combo and can be used to silence him.
* Global Silence will silence Timberaw no matter where he is on the map. This can be used to help allies get a kill on him, or prevent Timbersaw from killing someone.

* Shadow Dance allows Slark to not be targeted by Unstable Concoction, making Alchemist stun himself and making himself vulnerable to the enemy.
* Dark Pact also allows him to just purge off the stun if timed correctly.
* Essence Shift will steal stats over long durations at a time should Alchemist lack the damage to kill Slark.

* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.

* Bramble Maze prevents Timbersaw from Timber Chaining away without getting rooted.
* Cursed Crown can still catch Timbersaw if he Timber Chains away.
* Reactive Armor offers little protection against Dark Willow's high magical damage.

* Arcane Orb's pure damage ignores Timbersaw's Reactive Armor.
* Astral Imprisonment, if timed correctly, can interrupt Timber Chain, preventing him from escaping.
Additional:
* Arcane Orb deals constant pure damage, which bypasses Timbersaw's Reactive Armor.
* Sanity's Eclipse can hit targets inside Astral Imprisonment, which helps Outworld Destroyer finish off Timbersaw before he escapes with Timber Chain. It can also drain his mana, limiting his ability to escape should he survive.

* Corrosive Haze followed by Slithereen Crush takes advantage of Alchemist's main weakness, being physical damage before he has the change to improve his surviability with items.
* Bash of the Deep will deal lots of damage during the laning phase.

* Zeus deals enormous amounts of magic damage, being one of the best heroes to burst down Timbersaw early in the game.
* Lightning Bolt's mini-stun can stop Timbersaw's from escaping a fight with Timber Chain.
* Timbersaws tend to build health increasing items, making Zeus' Static Field deal huge amounts of damage.
Additional:
* Reactive Armor will not trigger from Zeus's spells or protect Timbersaw from their damage.
* Early game Timbersaw's strength is average and Zeus can heavily aid in bursting him down.
* Late game, if Timbersaw has built a lot of HP items, Zeus's passive Static Field will be more effective at chipping away Timbersaw's large HP pool.
* A Timbersaw who builds Pipe of Insight will be much more difficult to kill, as Zeus has no way to hold Timbersaw down, but Timbersaw will have less armor, mana, and damage than normal if he buys this item early game just to counter Zeus.

* Hex greatly reduces Timbersaw's mobility.
* The stun and damage over time from Shackles mitigates Reactive Armor's HP and armor regen.

* Ball Lightning makes Storm Spirit a target difficult to chase, even for a hero as mobile as Timbersaw.
* The magical damage from Static Remnant and Overload together with Storm Spirit's high mobility allows Storm Spirit to jump on Timbersaw and burst him down, even if he tries to escape.

* Rupture and Blood Rite locks down Timbersaw, preventing him from escaping with Timber Chain. However, Timbersaw may reflect a good deal of damage with Blade Mail.

* Feast is good against high health strength heroes such as Alchemist.
* Rage allows Lifestealer to not be targetable by Unstable Concoction, possibly making Alchemist stun himself.

* Brain Sap's pure damage ignores stacks of Reactive Armor.
* Nightmare prevents Timbersaw from using Timber Chain, setting him up for chain stuns and burst damage.
* Enfeeble highly reduces regeneration granted by reactive armor.
* Fiend's Grip immobilizes Timbersaw and drains his low mana pool, preventing escape afterwards. It also pierces Black King Bar.
* Bane's multiple disables often force Timbersaw or his teammates to spend gold on a Linken's Sphere.

* Time Dilation is similar to a long duration silence, making Timbersaw useless in team fights, or forcing him to adapt his build.
* Time Walk negates Timbersaw's burst damage.
* Time Lock provides magical damage and lock down, and is effective against both Reactive Armor and Timber Chain.
* In conjunction with Time Lock's magical damage, Chronosphere can destroy Timbersaw before he has time to react, and creates a large obstacle that obstruct's Timber Chain's mobility.

* Tidebringer will deal lots of damage to Alchemist before he builds physical survivability items.
* Torrent and X Marks the Spot can control Alchemist at all stages of the game before he has Black King Bar.
* Ghostship's rum buff will greatly reduce the Alchemist's damage output in teamfights including his Radiance.

* Alchemist is a well-known Radiance carrier among other auras your illusions will benefit from. They also get the extra move speed and reduced base attack time from his Chemical Rage, and it's even better if you can catch him as his own rage is about to expire.
* Disruption will buy enough time for all allies to retreat when Alchemist starts to activate Unstable Concoction.

* Timbersaw relies heavily on his abilities so Phantom's Embrace's silence makes it more difficult for him.
* Timbersaw cannot use Return Chakram or attack the phantom during Phantom's Embrace, forcing him to take full damage and refreshes Phantom's Embrace's cooldown.

* Hex greatly reduces Timbersaw's mobility.
* In addition, Lion can follow up with his Earth Spike and Mana Drain combo, preventing Timbersaw to escape with Timber Chain. And he can finish Timbersaw off with Finger of Death if the latter's HP is low enough.

* Reactive Armor's armor increase does not affects Muerta's Pierce the Veil despite Muerta often building high attack speed.
* Muerta's Dead Shot destroys trees preventing Timbersaw from escaping with his Timber Chain

* Heroes who build mana boosting items but have low mana regeneration are especially vulnerable against Mana Break and Mana Void: Timbersaw, Slark, Shadow Fiend, Clinkz, Bristleback Nyx Assassin, Magnus

* Clinkz can use Burning Army in teamfights which will cause a problem for Alchemist.

* In general, attacks of the melee heroes who are entirely reliant on dealing physical damage and/or have very little to no area-of-effect abilities will make Underlord tickle and will have no effect against him, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift to get to a designated point of the map: Phantom Assassin, Terrorblade, Troll Warlord, Drow Ranger, Phantom Lancer, Chaos Knight, Sven, Wraith King, Bounty Hunter, Alchemist, Templar Assassin, Nyx Assassin, Bane.

* In general, Timbersaw struggles against highly mobile heroes that can avoid his abilities: Puck, Weaver, Ember Spirit and others.

* Timbersaw has a difficult time against magical and pure damage: Lina, Leshrac, Enchantress, Queen of Pain

* Heroes who struggle to fight back against Sven at any point in the game are at a severe disadvantage: Alchemist, Anti-Mage, Crystal Maiden.

* Timbersaw has a difficult time against magical and pure damage: Lina, Leshrac, Enchantress, Queen of Pain

* Untouchable greatly reduces Chemical Rage's attack speed advantage.

* Timbersaw has a difficult time against magical and pure damage: Lina, Leshrac, Enchantress, Queen of Pain

* All Tinker's damage is magic/pure and completely ignores Timbersaw's Reactive Armor.
* Timbersaw very rarely builds Black King Bar, making him very vulnerable if Tinker builds Scythe of Vyse.

* Alchemist likes to farm fast and be ahead, unfortunately Lone Druid likes to do the same by taking towers.
* Acid Spray will never prove a threat to Lone Druid or his Spirit Bear.
* Chemical Rage may not prove so useful once Lone Druid procs entangled keeping him in place.
* Monkey King Bar is a very good choice on Lone Druid's Spirit Bear and it directly counters any potential Radiance from Alchemist.
* Assault Cuirass is another very good Spirit Bear item that further makes Alchemist vulnerable to physical damage, which is all Lone Druid does.
* Alchemist is not the kind of hero who wants to go on single target summon units, by the time he has killed the Spirit Bear his teammates might had already been slayed by his teammates. Not to mention Lone Druid can just resummon it, even if he is successful.

* Alchemist's reliance on fast attack speed to do single-target damage makes him vulnerable to Static Link. It also goes through Black King Bar, which is a standard item on Alchemist.
* Eye of the Storm is great against high health strength heroes as it reduces their survivability to physical damage.
* Razor has early lane push to counter Acid Spray.

* Axe can force Alchemist to attack him with Berserker's Call. High attack speed from Chemical Rage will cause Counter Helix to proc multiple times.
* This can get worse if axe has Blade Mail, which then returns all damage to Alchemist himself.
* Axe's abilities can pierce through Black King Bar, which is a common item for Alchemist.
* Berserker's Call grants Axe a huge bonus armor, which greatly counters Alchemist's physical damage for the most part.