First, you need to know what causes a runny nose. Common causes of a runny nose include allergies, sinusitis, colds, and more. Especially in autumn and winter, colds are one of the main causes of runny nose. In addition, some people are naturally more prone to nasal discharge. No matter what the cause of your nose is, the following 10 tips can help you stop it quickly. 1. Gargle with salt water. Gargling with salt water is a good remedy for nasal discharge.