Olloïs Histaminum Hydrochloricum 30C Vegan Organic, 80 Pel.Congestion, itchiness and sneezing are no match for Histaminum Hydrochloricum 30C, traditionally used for mild allergic reactions (coughing, sneezing, watery eyes).* Over the counter allergy medication, while addressing a myriad of symptoms, can leave you feeling tired and out of sorts. A Histaminum homeopathic remedy could be just what you need to find relief, without the side effects associated with more traditional medications.