systematic "glitch" in pages due to cache?

hello everybody, I have a real problem, and a vague description to it (can you guess?: newbie). I've created a site which retrieves a word from a database and displays it. The user enters another word (a translation) which is checked against the solution and feedback is given. These words are passed around in sessionvariables. Systematically after a while, I get a very slow loading of the page (and therefor the word i got from the database). In the end, i get my data, but it's slow and always with the same interval. I have a feeling this might be related to some garbage retrieval, or cache problem with the browser, but I can't figure it out. Does anybody has some suggestions? I'd really appreciate it! cheers, Simon