Materia Medica (English: medical material/substance) is a Latin medical term used for the body of collected knowledge about the therapeutic properties of any substance used for healing (i.e., medicines). Homoeopathic Materia Medica are encyclopedia of materials which may be used to prepare homoeopathic medicines. They list the materials along with details of the provings which establish the symptoms and conditions for which they are claimed to be suitable. They thus constitute a homoeopathic prescribing reference guide and are often used along with the Homoeopathic repertory.
Although there are various homoeopathic Materia Medica, written by different authors and covering different specialities, the term Homoeopathic Materia Medica is often used to refer the total sum of homoeopathic preparations and prescribing options. Hahnemann developed the first Homoeopathic Materia Medica by a system of homeopathic provings, where a substance was ingested by the "prover" and the symptoms that the "prover" developed were recorded in great detail. Materia Medica may also include accidental poisoning and some information from clinical treatment.