Picking bay in the wild is not recommended, as some plants commonly called bays or laurels are highly poisonous. Mountain laurel (Kalmia latifolia), cherry laurel (Prunus laurocerasus), bayberry (Myrica pennsylvanica), loblolly bay (Gordonia lasianthus) and West Indian bay (Pimenta racemosa) are highly toxic and should not be ingested.
California bay (Umbellularia californica), which I picked when I lived in California, has an aroma much like Laurus nobilis but the taste is much more concentrated and bitter. It should not be used in cooking (its principal constituent, umbellulone, can cause sinus irritation, convulsive sneezing and headaches), though many cooks still use it. Red bay (Persea borbonia) and swamp bay (P. borbonia var. pubescens) grow in the southern United States and the plants’ spicy leaves are successfully substituted for L. nobilis.
Click here for the original article, 2009 Herb of the Year: Bay (Laurus Nobilis).