Food allergies are known as the public health problem, affecting people of all age groups, but more commonly in babies and children, with consequences for nutritional status and quality of life.

Kefiran is a polysaccharide present in kefir grains that have been widely explored due to its potential health benefits. The objective of this work was to characterize and quantify the components present in the ethanolic extract of milk kefir grains; to study its pharmacokinetic and toxicological properties in silico and evaluate the acute toxicity of the kefiran in zebrafish. The prediction of pharmacokinetic properties was performed by QikProp software. In silico toxicity assessment was performed using the DEREK (deductive estimate of risk from existing knowledge) software. In the chromatographic, kefiran was identified as the major component. Results showed that the kefiran had low human oral absorption and intestinal absorption its due poor solubility profile; low logP value, indicating its lipophilicity and the low MDCK and Caco-2 cells permability, and unable to cross the blood–brain barrier. Kefiran did not present any structural warning for in silico toxicity. In zebrafish, the dose of 2,000 mg/kg of kefiran produced nonsignificant alterations in the analyzed organs. It can be said then that kefiran has an acceptable degree of safety for use in the development of drugs or functional foods. Further research such as in vivo testing to confirm its pharmacological potential is currently underway.