Contact with dogs is harmful to the body and may cause allergic reactions, respiratory infections, nematodes, bites and other hazards. 1. Allergic reaction: Because dogs have a lot of hair on their bodies, and there is also the phenomenon of hair shedding, if a person has long-term contact with dogs, it may lead to allergic reactions due to the hair, so that the body will appear red spots, itching, coughing, rashes and other symptoms. 2. Respiratory infections: due to the presence of a large number of bacteria, parasites and other pathogens in the dog, will enter the respiratory tract with the human respiration, stimulate the respiratory mucosa, resulting in infections, and in severe cases, bronchitis will occur. 3. Nematodes: Nematodes are parasites in the dog’s eyelashes or tear ducts, which can be transmitted to humans through mosquitoes, liquids, etc., and can lead to conjunctivitis, keratitis and other eye diseases, and in severe cases, blindness can occur. 4. Bite: some dogs are emotionally unstable, long-term contact with dogs may lead to scratching or biting, this time to timely vaccination against rabies. If the body caused other injuries, should go to the hospital in time for examination and treatment.