Religious laws do not usually forbid the use of psychotropic medication, but many do forbid the consumption of animal-based derivatives of bovine and/or porcine origin (e.g. gelatin and stearic acid) such as are found in many medications. Demonstrating awareness of this, combined with a genuine concern about how it affects the patient, may strengthen the doctor—patient relationship and avoid non-adherence. In this article, we outline dietary requirements of key religions and belief systems that may have a bearing when prescribing medication containing animal-based ingredients. We identify common psychotropics that contain animal-based derivatives and suggest alternative prescribing options and approaches to dealing with sensitive ethical issues.