The wife is having a rough time this year with hay fever. I asked her to try one of the suggestions below and she noticed improvement within a hour.
So for all of you that are overdosing on antihistamines, this post may help.
- A Specifically Designed Multispecies Probiotic Supplement Relieves Seasonal Allergic Rhinitis Symptoms.
- (Ecologic® AllergyCare; probiotik®pur) – Amsterdam, NL
- This probiotic mix comprises six different bacterial strains:
- Bifidobacterium bifidum W23,
- Bifidobacterium lactis W51,
- Lactobacillus acidophilus W55,
- Lactobacillus casei W56,
- Lactobacillus salivarius W57 and
- Lactococcus lactis W58.
- Probiotics (Lactobacillus gasseri KS-13, Bifidobacterium bifidum G9-1, and Bifidobacterium longum MM-2) improve rhinoconjunctivitis-specific quality of life in individuals with seasonal allergies: a double-blind, placebo-controlled, randomized trial.
- Probiotics modulate gut microbiota and health status in Japanese cedar pollinosis patients during the pollen season. 
- LGG – lactobacillus rhamnosus gg
- Effect of Lactobacillus rhamnosus GG and vitamin D supplementation on the immunologic effectiveness of grass-specific sublingual immunotherapy in children with allergy. 
- Allergy in marathon runners and effect of Lactobacillus GG supplementation on allergic inflammatory markers. 
- Improvements in seasonal allergic disease with Lactobacillus plantarum No. 14. 
- Probiotics in the treatment of Japanese cedar pollinosis: a double-blind placebo-controlled trial. 
- Specific probiotics alleviate allergic rhinitis during the birch pollen season. 
- Lactobacillus acidophilus (L. acidophilus) NCFM (ATCC 700396) and Bifidobacterium lactis (B. lactis) Bl-04 (ATCC SD5219)
The last item does not have any studies that I could find, I did find that with seasonal allergies that “The pollen season induced a reduction in Bifidobacterium, Clostridium and Bacteroides which could not be prevented by the [Lactobacillus, Bifidobacterium] probiotic intervention. “. The study did not try Miyarisan (Clostridium butyricum), which the wife found helped quickly.
Encouraging or supplementing Bifidobacterium and Clostridium as probiotics should reduce severity. Most of the studies used Bifidobacterium.