Armadas of jellyfish periodically besiege the Greek coasts, particularly in autumn, making swimming then a nerve-wracking activity. A variety of pain-relieving over-the-counter formulas are sold in Greek pharmacies, but failing that, home remedies include vinegar, baking-soda poultices and (it is claimed) urine.
If you graze against one of the many sea urchins that perch on Greek shore rocks, or worse step on one, the spines will lodge porcupine-style in your anatomy. If not removed, especially from feet, all but the tiniest fragments will fester or at least make subsequent hiking painful. Set to work with a sewing needle, the finest blade of your pocket knife (both sterilised) and olive oil introduced dropwise into the punctures. The oil floats the hollow, barbed spines, which can otherwise introduce bacteria deep into the flesh. Olive oil is also perfect for removing tar from your feet, quite a lot of which washes up on Greek beaches from time to time.