Brief Answer: Bile/bilirubin in the feces. Detailed Answer: Hello there, Nice to meet you here, I assume you mean to say about feces. The yellow color of feces is due to the presence of bilirubin [product from the gall bladder and liver], this helps in digesting fat consumed .Excess bilirubin are excreted with the feces making it yellow in color. Also consuming certain foods [like sweet potatoes or carrots] in excess may simply turns the feces appearence more yellow than the normal . Take care. Dr.surendiran

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