Dragon's Blood (originally from Sharn: City of Towers, the second link Amnestic posted is similar, but not exactly the same as the effect listed there) only had positive effect for sorcerers and people with dragonmark, everyone else could suffer the negative effects and the risk of overdose (which could happen from a single use) with no benefits.

The drugs required the user to make 2 saving throws. Failing the first save gives the user the first effect of the drug, failing the second save gives the secondary effect, both the effects and the DC were listed in each drug's description. On the first use, the user also had to make another save to see if they become addicted to the drug (with the DC and effect based on how addictive the drug was), and risk overdose under specific conditions. Addicted character had take the drug every few days (the period depended on the addiction's strength) to avoid withdrawal, which required them to make a save every day to avoid ability damage (the more serious the addiction, the higher the save DC and the damage on failure). 2 successful saves in a row cured the addiction.

Dragon's Blood is not a stimulant in the physical sense, and it does not get you high. It improves the user's magical abilities. All of them had the secondary effect of Cha damage (the stronger the drug... Black<Blue<Red, the more damage) and required Will save on each use to avoid overdose (which caused damage, once against increasing with the drug). The stronger versions also were more addictive. Black Dragon's Blood gave the user the ability to aply Enlarge or Extend spell metamagic for the next sorcerer spell of <3nd level or least dragonmark SLA, Blue Dragon's Blood made the next sorcerer spell of <5th level or least or lesser dragonmark SLA not expend the slot/use, and Red Dragon's Blood applied Maximised spell metamagic or increased the caster level by 3 for a sorcerer spell of <4th level or least or lesser dragonmark SLA. All benefits had to be used within 10 minutes of taking the drug, and could only be used once in 24 hour period.