Chlamydia is a bacterial infection, and cannot be cured by Threelac. Chlamydia is considered a Pelvic Inflammatory Disease (PID). This inflammation can cause scarring of the fallopian tubes, and permanently damage your girlfriend's ability to become pregnant someday. PLEASE, advise her to call her doctor right away and be tested.
Vaginal infections can be caused by many pathogens other than bacterium: such as yeasts (candida), parasites (one of which causes the trichomoniasis infections), and viruses. It is so important that your girlfriend request a full screening by her doctor.
NOW...it is possible your girlfriend is suffering from a yeast infection. Again...don't screw around with this!