Yes. You can. As a matter of fact, leaving a tampon in for too long can cause more serious health complications as well.
First, let’s address the question of a vaginal yeast infection. When a tampon is inserted, it is dry. As it is used, it becomes wet as it absorbs your menstrual fluids. The longer you leave the tampon in your body, the more absorbent it becomes. If you leave it in for too long, you experience leakage as the flow begins to absorb into the tampon’s cord and then out of your body. As this happens, you are no longer maintaining a clean, dry vaginal environment. The area becomes moist and dirty in addition to dark. This is the type of environment yeast loves, so leaving a tampon in for too long can contribute to the development of a yeast infection, especially if you’re already prone to developing them frequently.
The more pressing concern when it comes to leaving a tampon in too long is the potential for the development of toxic shock syndrome. Toxic shock syndrome, or TSS, is a bacterial infection that is caused by certain staph and strep strains. The strains associated with TSS usually live within the body quite naturally, but they release toxins. Tampons can absorb those toxins and, when the tampon is left in too long, can contribute to the possibility of the toxins entering the bloodstream. TSS is a very serious condition that can cause fevers, headache, low blood pressure, shock, kidney issues, and a host of other symptoms.
Either way, do your best to avoid both a yeast infection and TSS by using tampons carefully. You should be using the least absorbent variety necessary for your flow (ie. do not use a super-sized tampon on a light flow day thinking you can keep it in longer). Change the tampon every few hours and make sure your hands are clean during removal and insertion.
Finally, be sure to see your doctor or naturopath if you think you have a yeast infection or TSS. The sooner you get treatment, the better.