probiotic
Concise Oxford English Dictionary © 2008 Oxford University Press:
probiotic /ˌprəʊbʌɪˈɒtɪk/
▶adjective denoting a substance which stimulates the growth of microorganisms, especially beneficial ones such as those of the intestinal flora. ▶noun a probiotic substance or preparation.
'probiotic' also found in these Oxford entries:

