Eating an onion will generally not affect the results of the nucleic acid test, and patients should be careful to avoid drinking alcohol, smoking, and chewing gum before the test. Usually you can eat normally before the nucleic acid test, and it will not affect the test results, so you can eat onions before the nucleic acid test, no need to worry too much. Before the nucleic acid test, patients should pay attention to the fact that smoking, drinking and chewing gum are not allowed 30 minutes before the sampling, so as not to affect the test results. Meanwhile, when conducting the nucleic acid test, you need to wear a mask throughout the whole process, only remove the mask before the test, and wear it promptly after the test. And during the waiting period of the test, you need to keep a distance of 1 meter from other people and listen to the staff’s instruction in time. If the nucleic acid test is conducted through nasopharyngeal swab, some people may have the symptom of nasal bleeding, but most of the bleeding is small and does not require special treatment, if the bleeding is large, timely medical treatment is also required. It is recommended that usually before the nucleic acid test to understand its related matters, timely avoidance, but can eat normally, ate onions generally will not have an impact on the test results.