Certified GKH Gardening Expert
If you recently brought this plant indoors, this is a normal issue. It is just going through a bit of acclimation shock. Make sure it is getting enough light and water, but expect that it will shed yellow leaves all winter. Most of the time, hibiscus indoors are able to survive, but don't look that great. Not to worry though, they bounce back beautifully in the spring when you place them back outside.