Abstract: Solution administrable by intravascular injection in a human or an animal which comprises an effective amount up to 0.23% by weight of a benzalkonium fluoride having the formula: ##STR1## where R is an alkyl radical which may vary between C.sub.8 H.sub.17 and C.sub.18 H.sub.37, dissolved in an excipient injectable intravascularly. Preferably R is between C.sub.12 H.sub.25 and C.sub.14 H.sub.29, and more preferably C.sub.14 H.sub.29. The solution can be packaged in 10 ml ampoules, containing about 21 mg of benzalkonium fluoride, the benzalkonium fluoride being dissolved in a physiological solvent. The solution also contains at least one metallic derivative of fluorine, preferably lithium fluoride.