Listed below are some of the known interactions between LSD and other chemicals, plants or pharmaceutical medications. This is not a comprehensive list. Substances which are not listed below may still have significant and/or dangerous interaction with LSD.

CHEMICAL	Relationship	KNOWN ISSUES	POSSIBLE SYMPTOMS	REFS
Ritonavir Indinavir	Indirect Tentative Possibly-Extreme	Although no data exists directly about an interaction between Ritonavir and LSD, several case reports have been published in medical journals where individuals have had extremely severe adverse events after taking ergotamine and similar ergolines in combination with Ritonavir. Irreversible coma (Pardo Rey 2003), amputations (Liaudet 1999), numbness, and other symptoms of ergotism (severe vascular constriction) have been strongly linked to this combination. Because LSD's doses are so much lower than ergotamine and LSD is rarely used chronically, interactions of this type may not occur between Ritonavir and LSD. Ergotamine is also thought to interact dangerously with other pharmaceuticals such as erythromycin (Eadie 2001). There is no clinical data to suggest those other drugs cause dangerous interactions with LSD. This effect could also occur with other anti-viral metabolized through the same pathways.	nausea vomiting cephalagia peripheral-ischemia extremity-pain cyanosis	Liaudet 1999 Pardo Rey 2003 Caballero-Granado FJ 1997 Rosenthal 1999 Eadie 2001
If you have a negative drug interaction to report, please let us know.