The present invention provides illudin analogs of the general formula (I): where R1 is (CH2)n—X—Y or H; n is 0 to 4; X is O or S or N or absent; and Y is an optionally substituted (C1-C8)alkyl, (C6-C10)aryl, (C6-C10)aryl(C1-C4)alkyl or cyclo(C3-C6)alkyl optionally comprising one or more heteroatoms; a monosaccharide, an amino acid residue, or H when n is 2-4; R2 is absent; or R1 and R2 together comprise a 5-7 membered cyclic ring; R3 is (C1-C4)alkyl or H; R4 is H, SCH2CO2(C1-C4)alkyl, O—(C5-C12)aryl or —S—(C5-C12)aryl; R5 is H, OH or absent; R6 is (C1-C4)alkyl or absent; R7 is OH or OSi((C1-C4)alkyl)3; or R6 and R7 together are ethylenedioxy; R8 is optionally substituted (C1-C4)alkyl; and the bonds represented by ----- are individually present or absent. The invention further provides dimers comprising analogs of formula (I).