You can't eat hawthorn cake because hawthorn cake is sour. Eating sour food is not recommended during coughing. First of all, too sour food can easily irritate the throat, leading to cough or aggravating cough. Secondly, sour food has the function of astringent sputum, which makes it difficult to cough up sputum, which will aggravate the infection of respiratory system and make it difficult to recover cough.