It is essential for the growth of micro-organisms. It prevents the bacteriostatic properties of the drug since it has similar chemical structure as that of sulphonamides. It forms a portion of folic acid. Its role in human nutrition is not definitely known. It is found effective in combination with Inositol and Pantothenic Acid (vitamin B-5) to check premature hair greying, and changing back to black colour of the hair.

Dietary Sources: It is found in wheat germ, rice bran and polishing, milk, and in animal tissues.

Deficiency Indicators: Its deficiency can be responsible for achromotrichia in man due to change in intestinal micro flora. The deficiency of PABA can also cause premature greying of hair. It is reported to cause pancreatic enzyme deficiency. It might produce some rickettsial infection.

Recommended Daily allowance: The exact requirement or supplement is not established but the supply from daily balanced nutritive diet is adequate. Common food items like wheat germ, yeast, and liver abundant in other members of Vitamin B group will provide this Vitamin too for combination benefits.