Source Naturals(R) Allercetin(TM) Allergy & Sinus is a homeopathic remedy for the temporary relief of hay fever and pollen allergy symptoms such as sneezing, runny nose, itchy and watery eyes, plugged ears, congestion and headache. Allercetin can be taken any time during hay fever season, even before symptoms begin. Homeopathy is a special approach to good health that works by stimulating your body's own natural defenses to fight hay fever and allergy symptoms.