* 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.
Additional:
* Alchemist has a low starting armor and a low agility growth, which translates to a low armor growth . And since it is very uncommon for Alchemist to get straight to Assault Cuirass, or Shiva's Guard, Corrosive Haze makes him too vulnerable to physical damage, even with the hp regeneration of Chemical Rage

* Corrosive Haze will reveal Treant Protector even when he is under the effects of Nature's Guise.

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* 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.

* 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.

* 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.

* 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.

* Living Armor can be destroyed quickly with Ion Shell.

* 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.

* With Dual Breath, Liquid Fire and Macropyre Jakiro can quickly remove all Living Armor from a target.
* Ice Path allows Jakiro to prevent Treant Protector from using Overgrowth while staying at a safe distance.
* Macropyre destroy trees, which where Treant protector might be hiding

* 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.

* 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.

* 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.

* Not only are all of Timbersaw's active abilities capable of cutting down trees, but Whirling Death and Timber Chain also require it to be effective, counteracting both Treant Protector's Nature's Guise and Eyes in the Forest abilities.
Additional:
* Timbersaw can use his plethora of tree cutting abilities to level entire sections of the forest, making hiding in the trees more difficult for Treant Protector and his team.
* Timbersaw can easily cut down Treant Protector's Eyes In The Forest once his team has detection. He may even do it unknowingly due to the sheer destructive and chaotic nature of his abilities.

* 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.

* All of Treant Protector's abilities are worth stealing, and Rubick is able to cast them with no animation time.

* 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.

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

* Light Strike Array and Dragon Slave allows Lina to destroy trees, countering Nature's Guise and Eyes in the Forest.
* Lina has many tools to remove Living Armor's protection.

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

* Monkey King is one of the few other heroes who can easily traverse through trees, counteracting Treant Protector's ability to hide in trees.

* 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.

* Heroes with the capability of removing or destroying trees greatly hinders the effectiveness of Treant Protector's abilities: Batrider, Nature's Prophet, Lina, Enigma, Mars

* Invisibility reliant heroes: Heroes with invisibility abilities or those that have invested into invisibility items are hindered by Bounty Hunter's Track. Few examples of such heroes are:Clinkz, Riki, Treant Protector, etc.

* 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.

* 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.

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

* Heroes that wish to disrupt fights with spell combos or big ultimates are vulnerable to the long stun of Fiend's Grip: Disruptor, Death Prophet, Enigma, Faceless Void, Invoker, Lich, Magnus, Mars, Medusa, Outworld Destroyer, Phoenix, Puck, Queen of Pain, Shadow Fiend, Treant Protector, Underlord, Winter Wyvern, Witch Doctor, Zeus.

* Heroes with invisibility will be detected by Thirst when they have low enough health: Bounty Hunter, Templar Assassin, Riki, Clinkz, Weaver, Treant Protector, Nyx Assassin.

* Heroes with the capability of removing or destroying trees greatly hinders the effectiveness of Treant Protector's abilities: Batrider, Nature's Prophet, Lina, Enigma, Mars

Additional:
* Firefly will cut trees with ease, cleaning-up an area that's been enchanted with Eyes In The Forest, and potentially revealing a Treant under the effects of Nature's Guise.
* Batrider's DoT spells are also good versus Living Armor,

* Heroes with the capability of removing or destroying trees greatly hinders the effectiveness of Treant Protector's abilities: Batrider, Nature's Prophet, Lina, Enigma, Mars

* Doppelganger can dispel Leech Seed. It can also destroy large amounts of trees, counteracting Nature's Guise and Eyes in the Forest.

* 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.

* Heroes with the capability of removing or destroying trees greatly hinders the effectiveness of Treant Protector's abilities: Batrider, Nature's Prophet, Lina, Enigma, Mars

Additional:
* Nature's Prophet's treants can destroy trees to reveal Treant Protector is hiding on.

* Sprout is good for trapping melee carries with no escape abilities: Sven, Ursa, Alchemist, Lifestealer etc.