Key difference: Chyle is a milky bodily fluid that forms in the small intestine. The chyle forms specifically during digestion of fatty foods. Chyme, on the other hand, is a mixture of partly digested food and stomach fluids. It is termed as a ‘semifluid mass of partly digested food,’ and is also known as chymus.

Chyle and chyme are two different substances that are commonly referred to while discussing digestion.

Chyle is a milky bodily fluid that forms in the small intestine. It is essentially free fatty acids (FFAs), which are made up of lymph and emulsified fats. The chyle forms specifically during digestion of fatty foods. After digestion, the chyle is taken up by the lacteals, a type of lymph vessels, for distribution within the body. The lacteals have low pressure, which allows large fatty acid molecules to diffuse into them. This is in contrast to veins that have higher pressure, which only allows things like amino acids and sugars to diffuse into the blood directly.

Chyme, on the other hand, is a mixture of partly digested food and stomach fluids. It is termed as a ‘semifluid mass of partly digested food,’ and is also known as chymus. Once the food is eaten, it is partially digested and mixed in with the stomach fluids, which includes water, hydrochloric acid, and various digestive enzymes. This process make take anywhere between 40 minutes to a few hours from the time of eating. The mixture, known as chyme, then passes through the pyloric valve and enters the duodenum. The duodenum is the first section of the small intestine and is mainly where the extraction of nutrients begins.

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