Back in the early 80's my son was on the sublingual drops for allergy treatment so this is not a new form of treatment in the US. the doctor had told me that my son showed the most allergic reaction to dust mites that he had ever seen. He coughed all night and day and sniffed constantly. the original dosing plan had to be scaled back twice because of my son's reactions to the drops. He was 8 years old and could only tolerate one drop in the morning and one drop at night. the treatment went well for 2 years, but after 2 years there came a night when, after I had administered his drop, he came into my room gasping for air and managed to wheeze out that he could not breathe. Turns out he was coming down with a throat infection and the doctor had told me not to give him the drops if he was getting sick, but neither of us knew that. fortunately we had our emergency cabinet with asthma and allergy meds and managed to take care of this incident, but I was too afraid to ever give him any more drops. The very thought that he could stop breathing was too much for me to handle at home. He had already developed a good deal of allergy resisitance and even as an adult he just has some hay fever seasonally. I stopped taking allergy shots a few years ago after my arm developed a huge swelling like a golf ball after I was back at home. I decided to just stick with the antihistamines. the shots are not painful though - I could not even feel them.