TCBS Agar is a culture medium designed to selectively isolate Vibrio species, a group of bacteria that can cause a variety of foodborne and waterborne illnesses. It was developed by Kobayashi et al. in 1963 as a modification of Nakanishi's Medium.

TCBS Agar contains a variety of ingredients that make it selective for Vibrios. These include bile salts, which inhibit the growth of many other types of bacteria, and sucrose, which is fermented by most Vibrios. Vibrio cholerae, the most common cause of cholera, produces yellow colonies on TCBS Agar due to sucrose fermentation. Other Vibrio species, such as V. parahaemolyticus and V. vulnificus, do not ferment sucrose and produce blue-green colonies.

TCBS Agar is a highly sensitive and specific medium for the isolation of Vibrios. However, it is important to note that some other bacteria, such as Pseudomonas and Aeromonas, can also grow on TCBS Agar and produce blue-green colonies. Therefore, it is important to confirm the identity of any presumptive Vibrio isolates using additional tests.