(1) 1 allicin molecule consists of 6 carbon atoms, 10 hydrogen atoms and 3 sulfur atoms, so the atomic ratio of carbon, hydrogen and sulfur in allicin is 6:10: 3;

(2) The mass ratio of carbon, hydrogen and sulfur in allicin is12× 6:1×10: 32× 3 = 36: 5: 48;

(3) The sum of relative atomic masses of carbon atoms in allicin is 12×6=72, that of hydrogen atoms is 1× 10= 10, that of sulfur atoms is 32×3=96, and that of sulfur elements is 96.

(4) The mass of allicin is 36g12× 612× 6+/kloc-0 /×/kloc-0+32× 3×100% = 89g.

So the answer is: (1) 6:10: 3;

(2)36:5:48;

(3) Sulfur or sulfur;

(4)89.