Food intolerance (FI) is an adverse reaction to food caused by non-immune mechanisms, mainly related to digestive enzyme deficiencies (e.g. lactase deficiency), metabolic abnormalities (e.g. impaired absorption of fructose) or toxicity of food components (e.g. histamine). Unlike immune-mediated food allergy, FI symptoms are usually delayed (hours to days after ingestion) and mild, but are difficult to diagnose and manage clinically due to the complexity and variety of mechanisms that affect approximately 20% of the world's population.

The gut microbiota of food intolerance (FI) is different. The widespread use of artificial sweeteners (e.g. saccharin) can induce metabolic disorders by altering the structure of the intestinal flora, e.g. animal experiments have shown that the abundance of pathogenic bacteria (e.g. Bacteroides vulgatus) in the intestinal tract of mice ingesting saccharin was significantly increased, whereas the abundance of Akkermansia muciniphila was decreased, which led to impaired glucose tolerance and abnormal fat absorption, and ultimately increased the risk of obesity and diabetes mellitus. ultimately increasing the risk of obesity and diabetes . In addition, sorbitol, as a low-calorie sugar alcohol, can trigger osmotic diarrhoea when ingested in excess, while antibiotics combined with a high-fat diet further disrupts intestinal flora balance (e.g., Clostridia depletion), decreases flora sorbitol dehydrogenase activity, and leads to persistent sorbitol metabolism disorders.

Inclusion Criteria:

1. Food intolerance occurs through laboratory examination of at least two main foods
2. Underwent washed microbiota transplantation.

Exclusion Criteria:

1. Expected survival time <3 months;
2. Women who are pregnant or breastfeeding;
3. Other patients deemed not suitable for enrollment by the investigator.

Patients with food intolerance receiving WMT will be enrolled.