While Jim may comment on how to fix it, do you know what caused it? What camera did you use?
If you are in very normal daylight, then you can set most digital camera for Auto White Balance or else Daylight, and it will get it right. In other words, whites will be rendered as whites.
If you are inside, then you might have tungsten lights or fluorescent or something else. If you know which you have, then you can set the White Balance control to be that type. But if you don't know which it is, then you need to do a Custom White Balance. That means set up a pure white card (or gray, but it can't have any color tints at all) into the room light and shoot it filling the frame. Then go through the custom white balance procedure for your camera, which is typically in the menu, and you select that shot of the white card, and then tell the camera that is the white color. Then you move the control to Custom White Balance, and it will modify all future whites to be the same white that you told it was white. Once you leave the room, you can set your camera to Auto or something else, but the camera will remember the Custom setting until you tell it a different one in the future, like in a different room.
---Bob Gross---