Drugs

Drugs (薬 (くすり) , Kusuri^?) (medicine in the dub) are chemical substances developed by members of Yakuzen household (mostly by Kusuri), which have varied effects.

While some have been beneficial, most of them have caused trouble for - and even harmed - various members of Rentarou's Family. Some of the events in the series are due to the effects of drugs made by Kusuri.

List of Drugs

Name	Creator	Users	Effects	Lasts	Notes/Side Effects
Human Magnetizing Drug	Kusuri Yakuzen	Rentarou Aijou Kusuri Yakuzen Two delinquents	Allows the user's body to become magnetic.	10 minutes	If near a person who has drank the same drug with opposite polarity, both of them will become physically attracted to each other. The user will suffer three days and three nights of unimaginable, unbelievable, unheard-of constipation.
Night Vision Drug	Kusuri Yakuzen		Allows the user to see in the dark.
Ventriloquism Drug	Kusuri Yakuzen		Allows the user to make their voice appear to come from somewhere else.
Love Drug	Kusuri Yakuzen	Rentarou Aijou	Causes the drinker to fall in love with the creator.
Neutralization Drug	Kusuri Yakuzen	Kusuri Yakuzen Kusuri's Father Kusuri's Mother	Neutralizes the effects of most drugs.		Only applies to drugs that have been ingested orally. Some drugs, like the immortality drug, can only be neutralized temporarily. Cannot neutralize drugs that are sufficiently potent (e.g. improved version of immortality drug). Cannot neutralize some drugs safely due to causing strain on user's body.
Immortality Drug	Kusuri Yakuzen	Kusuri Yakuzen (prototype) Kusuri's Father (later version) Kusuri's Mother (later version) Yaku Yakuzen (near-perfected version)	Grants the user immortality, by granting them the physique of an eight-year-old human being.	Permanent	Can be temporarily negated with the neutralization drug. Earlier versions would cause the user's mental age to change when the drug was neutralized. Later versions allow the user to retain their mental age. The most recent version which Yaku has taken is a near-perfect version and cannot be neutralized.
Bust-Biggening Medicine	Kusuri Yakuzen	Karane Inda (rejected)	Increases the size of the drinker's bust.		The user's bust will be hard - akin to pectoral muscles instead of breast tissue.
Un-Twistify Medicine	Kusuri Yakuzen	Karane Inda (rejected)	Causes the drinker to become more sincere with their feelings.
Feminication Medicine	Kusuri Yakuzen	Karane Inda (rejected)	Causes the user to be more feminine.
Hot Stuff Medicine	Kusuri Yakuzen	Hakari Hanazono	Causes the user to become more sexy - by making their sweat be able to melt their clothes.	Single-use
BunBun-Fantasy Medicine	Kusuri Yakuzen	Shizuka Yoshimoto	The user will grow rabbit ears on their head. These ears are movable, and sensitive to touch.		The user's hearing is also enhanced for the duration of the drug.
Hair Control Drug	Kusuri Yakuzen	Nano Eiai Hahari Hanazono	The user can control their hair, akin to extra limbs.	10 minutes	Subsequent doses increase the user's risk of going bald. If used in conjunction with the hair growth drug - it causes the hair to have a life of its own, with potentially severe consequences.
Uncontrollable Urge to Kiss Lover Medicine	Kusuri Yakuzen	Hakari Hanazono (accident) Karane Inda (accident) Shizuka Yoshimoto (accident) Eiai Nano (accident) Chiyo Iin (accident)	If the user is male, it will increase their urge to be more physically intimate with their lover. If the user is female, it will increase their urge to be more emotionally intimate with their lover.	Permament (if not negated)	For female users, the drug affects their mental processes - removing all higher-brain functions except for wanting to kiss their beloved. Kusuri has termed this phenomenon as "turning into kiss zombies". Must be negated within one hour, or effects will be permanent.
Melt-Your-Face-Off Medicine	Kusuri Yakuzen	Kusuri Yakuzen	Corrosive substance which can cause severe chemical burns.		Can be negated by barriers between the drug and skin (including copious amounts of foundation).
Sleeping Medicine	Kusuri Yakuzen	Hanazono household's guard dog Shizuka Yoshimoto (accident)	Tranquilizer. Must be ingested orally.		Potent enough for a single drop to affect a decent-sized guard dog.
Infrared Eyedrops	Kusuri Yakuzen	Rentarou Aijou	The user will be able to see in the infrared spectrum - which includes body heat and security lasers.		While active, the user will not be able to see anything else beyond the infrared spectrum. Can be negated by washing the eyedrops out.
Complete-Makeover-Medicine	Kusuri Yakuzen	Rentarou's Family	Allows a person to alter their core personality. If multiple people in close proximity are exposed to this drug, can cause their souls to swap places (effectively switching bodies).		Souls can be released from bodies through a lover's kiss, so they can be restored to their original bodies.
Baby Transformation Drug	Kusuri Yakuzen	Rentarou's Family	Transforms the user into a baby.		Must be in effect for at least an hour before it can be safely neutralised.
Cuteness-Boosting Medicine	Kusuri Yakuzen	Shizuka Yoshimoto	An inhalant which causes people exposed to be sensitive to a person's natural cuteness.		During the karaoke date - the cuteness of Shizuka's singing voice was amplified to the point of literally blowing away Rentarou's Family.
Ear-Disintegrating Medicine	Kusuri Yakuzen	Hakari Hanazono (rejected)	Melts the user's ears off, rendering them deaf.	Permament	Cannot be neutralised.
Kissy-Kissy-Bang-Bang Lip Balm	Kusuri Yakuzen	Rentarou's Family	Lip balm which amplifies the hormones produced (and overall pleasure) when kissing.
Hair-Growing Medicine	Kusuri Yakuzen	Rentarou's Family	Stimulates hair-growth. The hair can be styled in any way possible, and also reset for subsequent styling.		If used in conjunction with the hair control drug - it causes the hair to have a life of its own, with potentially severe consequences.
De-Tsundere-fy Medicine	Kusuri Yakuzen	Karane Inda Rentarou's Family	Causes the user to release tsunde-rays from their body.		If taken by a tsundere person, it removes their tsundere side. If taken with the Tsundere-fy Medicine, allows the user to channel tsunde-rays between entities.
Tsundere-fy Medicine	Kusuri Yakuzen	Karane Inda Rentarou Aijou	Allows the user to absorb tsunde-rays from their surroundings.		Sufficient exposure to tsunde-rays can cause an ordinary person to become tsundere. If taken with the De-Tsundere-fy Medicine, allows the user to channel tsunde-rays between entities.
Formalin-like Goop	Kusuri Yakuzen	Kusuri Yakuzen	Special breathable liquid which mimics formalin. Worn as part of a costume.		May cause the wearer's urine to temporarily be more yellow.
Mega-Mega-Metabolism Medicine	Kusuri Yakuzen		Increases the drinker's metabolism significantly, allowing them to process any substances ingested at a faster rate.		If other drugs have been ingested, this drug reduces the duration of their effects.
Shrinking Drug	Kusuri Yakuzen	Nano Eiai (accident)	Shrinks the user's body.	Several hours (at least overnight)	Cannot be negated. The user must wait for its effects to wear off naturally.
100-Times-Weight Multiplier Medicine	Kusuri Yakuzen	Kusuri Yakuzen	Increases the user's body mass 100-fold, without changing their physical appearance.		Can backfire - if the user stands in an area which cannot support their weight.
Comatose Medicine	Kusuri Yakuzen	Hakari Hanazono (as Hakariet / Juliet Capulet)	Renders the drinker comatose.		Can cause death through overdose.
Flesh-Sticking Medicine	Yaku Yakuzen	Unnamed WWII Japanese soldier	Heals wounds, no matter how grievous.		Can cause unnatural swelling of body parts healed through this medicine.
Cold Medicine	Kusuri Yakuzen	Yamame Yasashiki (unused)	Cures colds.		Said to be at least three billion times more effective than store-bought medicine, though it has yet to undergo human testing.
Byakugan-Eye Drug / Nobita-Eye Drug	Kusuri Yakuzen	Kusuri Yakuzen Rentarou Aijou	Causes the drinker's eyes to scrunch up, resembling those of Nobita Nobi (from Doraemon).		Blinds the user, until neutralised. Originally intended as a Byakugan-eye drug, allowing the user to perceive their surroundings without having to move their head.
Unnamed drug	Kusuri Yakuzen		Can induce mania in the drinker.
Laugh Out Loud Drug	Kusuri Yakuzen	Chiyo Iin Aashii Kedarui (ineffective)	Causes the user to laugh uncontrollably.
Makes-Getting-Squished-Fun Drug	Kusuri Yakuzen	Kusuri Yakuzen	Allows user to enjoy being squished in cramped, enclosed spaces.
Super-Speedster Drug	Kusuri Yakuzen		Turns the drinker into a centaur - granting them corresponding superhuman speed.
Emotion-Eraser Medicine	Kusuri Yakuzen	Rentarou Aijou Iku Sutou	Temporarily deadens the user's emotions.
Kills You If You Aren't Thinking That The "Stacked Women-Ponytail-Knit Sweater" Combo is the Best Drug	Kusuri Yakuzen	Rentarou Aijou (accident)	Causes severe fever in the drinker, unless they think that seeing a stacked woman, with a ponytail and wearing a knit sweater, is the best.		Can cause death if not neutralized. Cannot be neutralized by conventional means. Fever can be broken by having stacked women in knit sweaters and hair done in a ponytail care for the drinker.
Kills You If You Aren't Thinking That The "Slender Lady-Pigtails-Pajamas" Combo is the Best Drug	Kusuri Yakuzen	Rentarou Aijou (accident)	Causes severe muscle straining in the drinker, unless they think that seeing a slender woman, with pigtails and wearing pajamas, is the best.		Can cause death if not neutralized. Cannot be neutralized by conventional means. Muscle straining can be relaxed by spending down time with as many slender women with pigtails and dressed in pajamas as possible.
Kills You If You Aren't Thinking That The "Small Girl-Hairbun-Overalls" Combo is the Best Drug	Kusuri Yakuzen	Rentarou Aijou (accident)	Causes rapid mental aging in the drinker, unless they think that seeing a small girl, with her hair in a bun and wearing overalls, is the best.		Can cause death if not neutralized. Cannot be neutralized by conventional means. Mental age can be reversed by spending innocent times with as many small girls with hair done up in a bun and wearing overalls as possible.
Gives-You-Fatal-Cherry-Blossom-Allergy Drug	Kusuri Yakuzen	Kusuri Yakuzen	The user becomes fatally allergic to cherry blossoms.		Best not to ingest while at a cherry blossom viewing.
Super Ultra Ultimatical Sleeping Incense	Kusuri Yakuzen	Rentarou's Family	An incense which helps people who inhale it fall asleep.	At least eight hours	Can induce nightmares in the user. Nightmares can be countered through a kiss from one's significant other.
Lets-You-Breathe-Underwater Drug	Kusuri Yakuzen	Rentarou's Family	Allows the user to breathe underwater.		Perfect for mermaid (or undersea creature) cosplay.