A foaming and silt suspending agent is disclosed containing at least one alkyltrimethylammonium chloride and an amine oxide selected from the group consisting of bis-(2-hydroxyethyl) cocoamine oxide, dimethylhexadecylamine oxide, and dimethyl-hydrogenated tallowamine oxide. The agent is particularly useful in a variety of aqueous based fluids of the type used in treating subterranean formations, including fluids containing other cationic additives such as certain acid inhibitors and clay stabilization agents which tend to impair the effectiveness of prior art agents.