Todd Hewitt Broth is recommended for cultivation of group A haemolytic Streptococci used for serological studies. This medium is also recommended for selective isolation of group B streptococci with added gentamicin and nalidixic acid. It is an alternative type in epidemiologic studies of group A streptococci as well as pathogenic microorganisms. With the addition of 15 g/l agar, the medium can be solidified and used as an excellent substrate for the production of capsules in streptococci.