This invention relates to solid oral compositions based on SAMe and/or NADH or theirsalts in association with calcium oxide and/or calcium hydroxide and a processfor obtaining them. This invention also relates to a method for stabilising asolid oral composition based on SAMe and/or NADH or their salts, making use of calciumoxide, calcium hydroxide optionally in association with malic acid, glutamicacid, xylitol, calcium sulphate hemihydrate, magnesium oxide and/or mixturesthereof. This invention also relates to the use of SAMe or its salts in associationwith calcium oxide and/or calcium hydroxide with the possible further additionof melatonin and/or l-the^anine and/or 1 -tryptophan and/or 5- hydroxytryptophan forthe treatment of depressive states.