If your eyes are consistently red, I would recommend an eye exam as there are multiple causes. The two most common are dry eye and allergies but there may be some other causes as well that may be important to address.

A safe drop to relieve redness is lumify . You can buy it over the counter and it can be used twice a day. You can also use non-preserved artificial tears. If these drops don't help you need to find the cause for your red eyes. It can also be due to other more significant eye diseases that an eye care professional can help you diagnose and treat your red eyes One 

Get your eyes examined

It is important to diagnose the cause of the redness in your eyes. After a diagnosis has been made a specific drop can be prescribed or recommended.