prō-sum, fŭi, prōdesse, v. n., to be useful or of use, to do good, benefit, profit.
I In gen., constr. with dat., a subject-clause , or absol. , rarely with ad or in and acc.: sibi prodesse, Enn. ap. Cic. Fam. 7, 6, 2 (Trag. v. 310 Vahl.); cf.: qui nec sibi nec alteri prosunt, Cic. Off. 2, 10, 36: multis, id. Lael. 1, 4: nihil tibi litterae meae proderunt, id. Fam. 2, 17, 7.—With subj.-clause : multum prodest ea quae metuuntur ipsa contemnere, Cic. Tusc. 4, 30, 64: iis carum et jucundum esse maxime prodest, Q. Cic. Petit. Cons. 5, 16; cf. id. ib. 11, 43: quid mihi fingere prodest? Ov. M. 13, 935: nec quicquam tibi prodest Aërias tentasse domos, Hor. C. 1, 28, 4; id. Epod. 17, 60; id. S. 1, 2, 113: quae scire magis juvat quam prodest, Sen. Ep. 106, 3.— Absol. : prodesse aequom est, Ter. Ad. 968: quorum altera prosunt, Cin. Fin. 3, 21, 69: studia aliena ac nihil profutura, Sall. J. 1, 5: magis tamen Menenianum profuit judicium, Liv. 2, 52; Quint. 4, 1, 3; 11, 1, 9: quae nocuere sequar, fugiam quae profore credam, Hor. Ep. 1, 8, 11: aut prodesse volunt aut delectare poëtae, id. A. P. 333: tu tantum corpore prodes, Nos animo, Ov. M. 13, 365.— With ad or in and acc.: id mirum, quantum profuit ad concordiam civitatis, Liv. 2, 1: in id quoque prodest, ut, etc., Quint. 8, 3, 9: in commune, id. 6, 1, 7.—With abl.: constantia multum prodest in amore, Prop. 2, 26, 27.—
II In partic., of medicines, to be good , be beneficial : fabam voci prodesse, Plin. 22, 25, 69, § 141: balineum assumo, quia prodest, Plin. Ep. 7, 21, 3: ad tormina, Plin. 22, 25, 63, § 131: contra ignem sacrum, id. 20, 7, 25, § 59.—With inf.: contra anginas tritum in poscā gargarizare prodest, Plin. 20, 6, 23, § 52.