BACKGROUND/OBJECTIVESThin children may have insufficient intake of energy and nutrients, resulting in reduced immune function and growth. This study aimed to identify the effects of multiple herb formula SEC-22 supplementation on growth, dietary changes, and picky eating behaviors in thin children.SUBJECTS/METHODSA double-blind, randomized clinical trial was conducted on 79 children aged 2-5 years with poor appetites, BMI percentile < 25, and without any illness. Subjects were given either SEC-22 (n = 35) or placebo (n = 44) for 2 months and followed for an additional 2 months. Three-day dietary records, questionnaires on picky eating behaviors, and anthropometric measures were collected.RESULTSEnergy, carbohydrate intake, and feeding difficulty improved in both groups during the intervention period. However, changes were maintained only in the SEC-22 group after 2 months of follow-up post-supplementation. 'Frequency of trying to feed' was improved in the SEC-22 group compared to the placebo group after the first month of follow-up (P < 0.05). Intakes of potassium and thiamine were improved in the SEC-22 group compared to the placebo group after the first month of intervention (P < 0.05). 'Frequency of food reward', eating amount, and intakes of carbohydrate, potassium, and vitamin C showed significant improvement compared to the placebo group after the second month of follow-up (P < 0.05).CONCLUSIONSThese results suggest that SEC-22 supplementation can improve parental feeding difficulty resulting from insufficient eating amount or picky eating as well as increase nutrient intake in thin children. Although these improvements were observable at least 2 months after supplementation, effects beyond this time frame need to be confirmed.