Spider toxins in the venom of Nephila clavata L. Koch were investigated and 4 kinds of closely related toxic components, JSTX-1, 2, 3 and 4, were chemically characterized as follows: JSTX-1, 2,4-dihydroxyphenylacetylasparaginyl spermine; JSTX-2, N-(2,4-dihydroxyphenylacetyl-ornithyl-asparaginyl)-N'-(putreanyl-putreanyl) cadaverine; JSTX-3, N-(2,4-dihydroxyphenylacetyl-asparaginyl)-N'-(aminopropyl-putreanyl) cadaverine; JSTX-4, N-(2,4-dihydroxyphenylacetyl-asparaginyl)-N'-(arginyl-ornityl) cadaverine. The toxins inhibited glutaminergic neurotransmission in arthropods.