Moderate bacterial conjunctivitis might improve without antibiotic therapy and without creating any kind of problems. It typically improves in 2 to 5 days without therapy but can take 2 weeks to disappear entirely. The infection will usually clean up in 7 to 14 days without therapy as well as with no long-lasting repercussions. However, in many cases, viral conjunctivitis can take 2 to 3 weeks or even more to clean up.