People can be allergic to red yeast rice if it is inhaled, notes WebMD. Its safety if taken by mouth is uncertain, and it is advised that pregnant and lactating women should not consume it.
Some reported reactions to red yeast rice inhalation include inflamed eyes, swollen skin and hives, itchiness, and breathing problems, states Mayo Clinic. While side effects are described as rare with moderate use of this product, diabetics and people who have allergic reactions to rice and statin drugs should also avoid red yeast rice. The Mayo Clinic recommends avoiding doses higher than 2.4 grams on an ongoing basis, with a 12-week cut-off for ingesting the supplement.