Original: In humans, signs and symptoms of riboflavin deficiency (ariboflavinosis) include cracked and red lips, inflammation of the lining of mouth and tongue, mouth ulcers, cracks at the corners of the mouth (angular cheilitis), and a sore throat.
Simplified: Riboflavin deficiency can cause a sore red mouth, sores in the mouth (mouth ulcers), cracked red lips, cracks at the corners of the mouth (angular cheilitis), and a sore throat.