Spider plants are not poisonous to cats, although sensitivity to the plant may cause an allergic reaction, such as skin irritations, according to the University of Connecticut's home and garden extension website. There are, however, many common household flowers and plants that are poisonous.
Many household plants, with the potential to poison a cat ,require ingesting copious amounts before any reaction occurs. Poisonous plants often taste bitter or have a pungent odor that repels the cat, before ingestion. Daffodil, mistletoe, Calla lilies, amaryllis, aloe vera and azaleas are common indoor and outdoor plants that are poisonous. Better choices for households with pets include African violets, geraniums, coleus, jade, impatiens and Boston fern.