* 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.

* Dark Pact dispels Ignite's slow and Fireblast's stun.
* Shadow Dance allows Slark to regenerate HP, even when he is affected by Ignite and Fireblast.

* 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.

* Lifestealer's Rage makes him immune to all of Ogre's magical debuffs and also dispels them.
* Ogre's high health pool makes him an ideal target for Feast.
Additional:
* Ogre Magi has nothing against Rage and his high health pool amplifies Feast.

* 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 breaks Multicast.
* Corrosive Skin minimizes the damage from Ignite and Fireblast.

* 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.

* Puck silences Ogre Magi with Waning Rift, and Phase Shift makes Puck untargetable for the duration.

* Ogre Magi has single-targeted magical-only damage and disables and is less effective against Meepo's clones.

* Heavenly Grace reduces Fireblast stun time and dispels Ignite.
* Purification can heal damaged heroes if needed.

* 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.

* Ogre Magi only deals magical damage, which Anti-Mage is exceptionally resistant due to Counterspell.
* Anti-Mage dispels Ignite with Manta Style.
* Ogre Magi has a very large mana pool which means Anti-Mage can do large amounts of damage to him with Mana Break and Mana Void.

* 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.

* 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.

* Fate's Edict gives full immunity from Ogre Magi's mostly magical damage.
* Fortune's End can dispel Ignite (when used on allies) and Bloodlust (when used on enemies).
* False Promise can dispel Ignite and Fireblast.

* 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.

* 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.

* 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.

* 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.

* 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.

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

* 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.

* Phantasm dispels Ignite and makes targeting the real Chaos Knight much harder.

* 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.

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

* Visage can quickly kill heroes with low to medium base armor and no innate escape mechanism. Examples include Alchemist, Crystal Maiden and Zeus.

* Arc Warden's Tempest Double is helpful for killing Ogre Magi who lacks AoE damage and disables.

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

* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

* 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, heroes that deal burst in multiple instances will trigger Borrowed Time and heal Abaddon for a large amount, such as Skywrath Mage, Techies, Juggernaut, Shadow Shaman, or Ogre Magi.

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

* Earth Spirit's useful kit of Slows, Stuns, and Silences can set up kills on Ogre Magi and the silence can stop him from using his abilities.

* Winter Wyvern's Winter's Curse works very well against the increased attack speed from Bloodlust.

* 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

* 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.

* Ogre Magi has no undispellable AoE damage or disables and has nothing to deal with Phantom Lancer's illusions.
* Doppelganger disjoints and dispels Ignite.

* Alchemist has very bad armor and does not build armor items for the large majority of his build, so Jingu Mastery and Wukong's Command can be very deadly.
* Desolator, Sange and Yasha or Diffusal Blade can all be purchased to increase your damage against Alchemist or just to keep your movement speed high enough to match him while Chemical Rage is active.
* Monkey King is an agility hero and scales with armor, so Acid Spray loses it's effectiveness later in the game.