If your vehicle is showing fresh oil dripping from the bottom of the engine, here are the most likely causes and the parts you'll need to fix each one.
The drain plug was not tightened properly during a recent oil change, or its sealing gasket is missing, crushed, or reused too many times.
The oil filter is loose, or the old filter's rubber O-ring stuck to the engine block creating a 'double gasket' blowout that rapidly leaks fresh oil.
The gasket sealing the top of the engine has hardened and failed. Oil leaks from the top and runs down the sides of the engine block, dripping off the bottom.
The seal between the engine block and the oil pan at the very bottom of the engine has degraded over time, allowing oil to seep out.
The plastic housing of the oil pressure sensor can crack or its internal seal can fail, causing oil to spray or drip down the side of the engine block.
The large seal around the rear of the crankshaft is worn out, causing oil to drip from the seam where the engine meets the transmission.
The seal at the front of the engine behind the main pulley is worn out, slinging oil down the front of the engine block and oil pan.