Hello dear. Gnat flies may cause bites and thus infection. But swallowing gnat flies in food or drink may not cause much problem except for some gastritis. If you want to know i can tell you a few infections transmitted by bites of gnat flies. Not all gnats transmit diseases, but yes there are some that can transmit several diseases like: 1. “River blindness” that causes infected individuals to lose sight. 2. “Leishmania (Kala- Azar)” that causes cutaneous sores on the body. 3. “Oraya” and “Sandly” Fever. 4. Carrison’s disease. 5. “Toscanca” and “Punta Toro” Virus If a gnat as bitten you then you should follow below steps: 1. Disinfect the area: This is the most important thing that you can do after a gnat has bitten you. Clean the area with soap and water thoroughly. You could also clean the area with any alcohol based or vinegar based disinfectant. 2. Apply an Antiseptic: If you feel you can also apply an antiseptic swab over the wound. This is a good idea if you want the wound to heal quickly without any other complications. 3. Anti-Itch or Pain relief: If you are experiencing a lot of pain of itch then you should visit a Doctor and he will prescribe you an anti-itch (antihistamines) or pain-relief medicine depending on your condition. Do not scratch the wound as it will open the wound for other bacterial infections. 4. Know when to visit a Doctor: Visit a Doctor in case you experience any of the following symptoms after the bite: i. If the area around the bite is very swollen. ii. If you have a hard time breathing, or get hive iii. If you feel swelling of the throat, chest and mouth. iv. If the wound begins to drain yellow or greenish fluid (pus). Hope i have answered your question. Feel free to contact me if you have any more questions. I ll be glad to help you. All the best With warm regards Dr Sanjay Kini