The side effects of bird’s nest are as follows: 1. Infected patients are very likely to have increased symptoms of infection after eating bird’s nest, such as upper respiratory tract infections like colds, which can make fever symptoms significantly worse after taking bird’s nest, and colds are not easy to get well. 2. Bird’s nest has strong tonic properties and is rich in protein, which can cause allergies in many patients. The most important side effect of bird’s nest is that it can help to accelerate the reproduction of advanced tumors, which is not beneficial to the containment of the disease.