Determine quality: For potions purchased from apothecaries, hedge wizards, and the like, roll 1d12. A result of 12 (or greater) indicates a standard potion with only token negative effects at most. For potions found in treasure hoards, you may want to roll a d20, or apply a bonus to the d12 roll to produce a higher probability of better potions.
Optionally, Poor potions have only half normal duration, and half normal or faulty effect (for example, an invisibility potion might make the imbiber transparent rather than completely invisible.) Fair potions use one die size smaller when rolling for duration and any randomly determined effects. Good potions have full effect and duration.
Determine side effects: Roll 1d20 and consult the table below. All effects last for the duration of the potion, unless otherwise noted. Potions that are permanent, such as healing potions, are considered to have standard durations for the purpose of side effects. Note also that no ability score will be reduced below 3 by any penalties.
*Notes on body change/polymorph: These are at the DM's discretion, ideally tailored to the specific potion. For example, a potion of water breathing might change parts of the character to fish parts. A serious handicap might give him gills, making him unable to breathe air. A moderate handicap might make his hands into fins so that he can't hold weapons. A minor handicap could change his head to a fish head, making him unable to speak clearly. A potion of healing might cause the character's feet to become roots (absorbing nourishment from the earth but immobilizing him), cause his flesh to swell, forcing him to remove his armor, or give his skin a "healthy glow" that foils attempts at stealth.
| Quality: 1d12 -->
||1-3 Poor||4-8 Fair||9-11 Good|
|1||Poison||1d6 points of damage per turn for potion's duration.||1d3 points of damage per turn for the potion's duration.||1 point of damage per turn of the potion's duration.|
|2||Paralysis||Paralyzed for half the potion's duration.||Paralyzed for 1 turn.||Paralyzed for 1d6 rounds.|
|3||Mute||Unable to communicate verbally or cast spells for the potion's duration.||Unable to communicate verbally or cast spells for half the potion's duration.||Unable to communicate verbally or cast spells for 1 turn.|
|4||Drowsiness||Cannot stay awake longer than a minute at a time for the potion's duration; must be awakened by another character. While awake, Int and Dex halved.||Save vs. spells each turn of the potion's duration or fall asleep. While awake, Int and Dex -2.||Int and Dex -2.|
|5||Euphoria||Wisdom reduced to 3.||Wisdom halved.||Wisdom -3.|
|6||Dizziness, vertigo||When not guided by another character, save vs. paralysis each round or fall down. -4 to all attack rolls.||May walk at half speed unassisted. Save vs. paralysis or fall down when making any sudden moves (such as in combat.) -2 to attack.||Save vs. paralysis when struck in combat or fall down. -2 to attack.|
|7||Amnesia||Forget events of the past 24 hours, including spells memorized.||Forget the events of the last hour.||Forget the events of the last turn.|
|8||Weakness||Strength reduced to 3.||Strength halved.||Strength -3|
|9||Lethargy||Movement reduced to lowest line of encumbrance table (whether or not encumbrance rules are used.)||Movement halved.||Movement reduced by one line on the encumbrance table.|
|10||Intoxication||Int, Wis, Dex, -4.||Int, Wis, Dex -2||Int, Wis, Dex -1|
|11||Body change /polymorph||Serious handicap, DM's choice*||Moderate handicap, DM's choice*||Minor handicap, DM's choice*|
|Unable to cast spells or move quietly.||Spells and quiet movement spoiled 1-3 on 1d6.||Spells and quiet movement spoiled 1 on 1d6.|
|13||Hunger||Str, Dex, Con reduced to half; alleviated by consuming quadruple rations for one day.||Str, Dex, Con reduced to half; alleviated by consuming triple rations for one day.||Str, Dex, Con -3; alleviated by consuming double rations for one day.|
|14||Sensitivity to light||Full daylight causes 1 point of damage per turn, -4 to attack. -2 to attack in torchlight or similar.||-2 to attack in daylight, -1 in torchlight.||-1 to attack in daylight.|
|15||Sensitivity to pain||Suffers +3 damage from physical attacks.||Suffers +2 damage from physical attacks.||Suffers +1 damage from physical attacks.|
|16||Sensitivity to heat/cold||Suffers +3 damage from heat or cold attacks. 1d4 damage per turn from exposure to environmental heat or cold (e.g. bonfire, cold water, hot or cold weather.)||Suffers +2 damage from heat or cold attacks. 1 point of damage per turn from exposure to environmental heat or cold.||Suffers +1 damage from heat or cold attacks.|
|17||Numbness, tremors||Dexterity reduced to 3.||Dexterity reduced by half.||Dexterity -3.|
|18||Hallucination||Experience the equivalent of a phantasmal force spell of something fearful or threatening.||Experience the equivalent of a phantasmal force spell, but non-threatening.||Hear phantom noises or voices at random.|
|19||Loss of vision||Blinded.||Blurred and double vision. Sight distance ¼ normal. -2 to melee attacks. Missiles automatically miss.||Blurred vision. Sight distance ½ normal. -2 to missile attacks.|
|20||Loss of hearing||Deafened. Surprised 1-4 on 1d6 if alone. Spell casting fails 1-4 on 1d6.||Partly deafened. Surprised 1-3 on 1d6 if alone. Cannot distinguish voices in noisy situations such as combat (i.e. no communication from other characters allowed.)||Muffled hearing. Surprised 1-3 on 1d6 if alone. Standard
hearing check to heed communications in noisy situations.