Diuretic and antihypertensive effects from nine comestible plants (Allium cepa Linn., Allium sativum Linn., Carun petroselirumBenth & Hook., Citrus limonum Risso, Nasturtium officinale R. Br., Ocimum micranthum Willd., Olea europaea Linn., Sechium edule S.W. and Zea mays Linn.) have been investigated in conscious rats. The fresh, finely cut plant (5% weight/vol) was extracted in 50% ethanol during 3-7 days. After evaporation to 1/3 of initial volume the extract was administered p.o. The diurese (vol.) or arterial pressure was measured in normal female and male SHR rats respectively. The diuretic effects were moderate. Allium sativum Linn., Olea europaea Linn. and Ocimum micranthum Willd, produced antihypertensive effects while Nasturtium officinale R. Br increased the arterial pressure. It is concluded that some plants largely used as aliments might have important effects on arterial pressure.