Man has always found food and medicines in plants, which justify his particular interest. With the development of modern medicine, interest in plants has increased due to the bioactive molecules found there and used as active ingredients. Among these molecules, alkaloïds are highly sought-after nitrogen compounds because of the interesting pharmacological properties provided by these types of molecules. They are found in living organisms, particularly in plants. Alkaloïds of natural origin, which are used in modern medicine, are highly appreciated, such as morphine, quinine, caffeine, and codeine. However, their extraction from plants should attract particular attention. The extraction of alkaloïds is based on their basic character and solubility profile. Generally, alkaloïds are extracted using mainly three methods: extraction with non-polar organic solvents in alkaline media, extraction with polar organic solvents, and extraction with acidified water. This chapter aims to present and describe the different procedures for extracting alkaloïds from medicinal plants.