In 1992 in El Paso, TX a randomized, double-blind, placebo controlled study silymarin of subjects (n=130) with allergic rhinitis in 1992-1993 was conducted. the average ige level of the placebo treated subjects remained essentially flat, while the average ige level for active treated subjects was reduced significantly from baseline to day 30.7 in 1993 in el paso, tx, valid subjects (n=66) returned a second set of symptom diaries which they had completed for days 365 to 395 (the same period, one year after silymarin milk thistle extract and silymarin the first set of symptom diaries). the active group had mean symptom scores showing statistically significant decreases from 1992 to 1993. the placebo group had increased symptoms in silymarin 1993. (the relevant pollen counts at the study site in 1993 were much higher than in 1992, leading to expectation of higher symptoms.)7

in 1990 study in san diego, ca the 5 active subjects with allergic rhinitis had a lowered total serum ige from day 0 to day 90 while 4 placebo subjects, (2 with allergic rhinitis, 1 with asthma and 1 with both), had flat or increased ige levels.4 in a randomized, double-blind, silymarin placebo controlled study of symptoms and serum ige levels in san diego, ca in mid-1991, subjects had allergic rhinitis and/or asthma. serum was drawn at day 0 and day 30. seven of the 10 active treated subjects had a reduction in total serum ige levels. in 10 placebo treated subjects, 5 had levels of total serum ige that stayed the same (plus or minus 5%), 3 decreased and 2 increased.5 statistical analysis of the open-label study as well as the double-blind randomized placebo controlled study have shown a significant effect of vitamin b12 in lowering serum ige concentrations.