A pilot randomized trial showed that a single high dose of psilocybin was more effective than nicotine patches in helping smokers quit smoking. Psilocybin was administered in combination with cognitive behavioral therapy (CBT). Among 44 participants (22 in each group), psilocybin achieved biochemically verified 7-day abstinence at 12 months in 59% versus 27% with nicotine patches. In continuous abstinence, it was 36% for psilocybin versus a lower percentage for patches. In a previous open-label pilot study with 15 participants, 6-month abstinence was higher than with conventional medication or CBT alone. Long-term data from this study recorded 60% abstinence at 12 months and 60% at an average of 30 months. Greater mystical effects of psilocybin were associated with greater success in quitting. A larger randomized trial is underway to verify efficacy.