The ceiling of the oral cavity is called “palate” in medicine, and the yellowing of the palate may be the manifestation of coccidioidomycosis, oral candidiasis, exogenous coloration or ulcers, etc. It is recommended to go to the hospital for examination and treatment. 1. When Staphylococcus aureus, hemolytic streptococcus and other genera stimulate the palate mucosa, the oral ceiling may appear grayish-yellow pseudomembrane, and in severe cases, vesicles appear. 2. Long-term use of antibiotics, malnutrition or immunodeficiency may develop oral candida infections, and white or yellow spots and patches may appear on the surface of the oral mucosa. 3. Eating yellow foods or medications may cause the mucosa to stain for a short period of time. 4. When ulcers appear, the ulcerated surface usually appears white or yellowish-white.