Alterative is a former categorisation of materia medica covering various substances, often metals or minerals used in the treatment of chronic conditions to alter the body's metabolic processes.
[1] Substances included in this category included iron, mercury, phosphorus, manganese and arsenic,[2] as well as iodine.
[3] In modern medicine these are categorised separately according to the biochemical nature of the change they bring about and their categorisation as "alteratives" has become obsolete.
[2]