Hi, Neti pot becomes popular among people who suffers from sinus problems. It is used to help clear out nasal blockage with the help of saline water or normal water. But, the FDA has given a warning to its users: it is very much important to obey the neti pot s instructions, as in some cases, though it is rare, improper using of this device may promote to develop life threatening infection caused by amoeba Naegleria fowleri. If using the water into nasal passages, contains such type of amoeba, then it may develop a rare type of brain infection that is known as primary amoebic meningoencephalitis or PAM. This type of amoeba may be found in lake water, stream water or even tap water. The clinical features of primary amoebic meningoencephalitis are severe headache, fever, neck stiffness and many more. This disease kills few people in America in every year according to the CDC. But, though it is very rare, so you should consult your doctor immediately for further evaluation of your neck stiffness and then treat accordingly. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician