San Pedro cactus may refer to several species or infraspecies of cactus potentially containing mescaline, particularly:

• Trichocereus macrogonus var. pachanoi, synonyms including Trichocereus pachanoi and Echinopsis pachanoi

but also:

• Echinopsis cuzcoensis
• Echinopsis lageniformis
• Trichocereus macrogonus
  • Trichocereus macrogonus var. macrogonus, synonyms including Trichocereus peruvianus and Echinopsis peruvianus