A new solanocapsine‐type alkaloid named aculeamine has been isolated from roots of Solanum aculeatum and its structure has been established by X‐ray analysis as 22,26‐epimino‐23β‐methoxy‐16α,23‐epoxy‐5α,25αH,25βH‐chloestane‐3β‐ol. The compound crystallizes in the hexagonal space group P61 with the lattice parameters a = b = 16.706, c = 17.056 Å, α = β = 90°, γ = 120°. The final residual value was R = 0.079. Copyright © 1984 WILEY‐VCH Verlag GmbH & Co. KGaA