Azelaic acid gel and metronidazole gel with the use of the general need to stagger the time, can be used separately in the morning and evening, or the first use of metronidazole gel, 30 minutes before using azelaic acid gel. 1. Separate use in the morning and evening, use metronidazole gel in the morning and azelaic acid gel before going to bed or azelaic acid gel in the morning and metronidazole gel before going to bed. It should be noted that azelaic acid gel in the use of, to gradually build up tolerance, such as early to take a small area of spot application, no discomfort gradually take the way of application. 2. In the case of skin tolerance can be used first metronidazole gel, wait 30 minutes, the drug is basically absorbed after cleaning the affected area. Then use azelaic acid gel, massage until absorbed, if this combination of skin irritation is greater, then the first method. Azelaic acid gel and metronidazole gel combined use is often seen in the treatment of rosacea, rosacea and other diseases, it usually takes about 1 ~ 2 months to see the initial effect, if the use of severe irritation during the dermatitis, need to stop using. If you need to use the drug need to be used under the guidance of a doctor, do not abuse, so as not to delay the condition.