Phenylhydrazine is a toxic compound that can induce a range of adverse effects in the body, including haemolytic anaemia, liver damage, and oxidative stress. Phenylhydrazine and its derivatives were initially used in medicine at the end of the nineteenth century, although with limited success. At high concentrations, Phenylhydrazine causes haemolytic anaemia. It causes haemolytic anaemia by causing the loss of red blood cells due to oxidative stress within erythrocytes and alterations at the cellular level. Other Phenylhydrazine adverse effects include the production of Methaemoglobin and Heinz bodies. This substance has the ability to influence immunological responses. Phenylhydrazine was originally used to treat hemocytopenia, a condition that causes damage at several levels in various organs. Various herbal supplements with single or multiple biological activities have been reported to be effective and beneficial against anaemia caused by Phenylhydrazine derivatives tested on rats because they have anti-oxidant, anti-inflammatory, cytoprotective, immunomodulatory, and anti-anaemic effects, depending on the phytochemical constituents present in the particular plant.