A term for para-aminobenzoic acid, a factor in the vitamin B complex.
Para-aminobenzoic acid or PABA was initially labeled as Vitamin Bx when it was previously believed to be a vitamin of the B complex, without the numerical designation. However, with further studies it was not found to be technically a vitamin for humans (and other large animals). In fact, PABA is a vitamin for many bacterial species, such as bacteria in intestines. The intestinal bacteria are capable of using PABA to produce folic acid, an ability which humans lack.
Also called: para-aminobenzoic acid, bacterial Vitamin H1.