If you have a seemingly insurmountable problem, you must do things you ordinarily would not do in order to solve it.
Bulgarian translation / превод на български език
Извънредните ситуации се решават с извънредни мерки.
Contribution by Elmira Kotscheva
French translation / traduction français
Aux grands maux, les grands remèdes.
Contribution by Marjorie Yerushalmi
German translation / Deutsch Übersetzung
Außerordentliche Übel erfordern außerordentliche Mittel.
Greek translation / ελληνική μετάφραση
Kατά την αρρώστια και το φάρμακο
Latin translation / translationem Latinam
Extremis malis extrema remedia.
Italian translation / traduzione italiana
A mali estremi, estremi rimedi.
Contribution by Vincenzo Albanese
Portuguese translation / tradução em português
A mal desesperado, remédio heróico./
Para grandes males, grandes remédios.
Contribution by Ana J. Andrada
Brazilian Portuguese translation / tradução em português
Situações extremas requerem medidas extremas.
Contribution by Carlos A R de Souza
Romanian translation / traducere în română
Pe durerea mare alta mai mare o tămăduiește.
Russian translation / русский перевод
Клин клином вышибают.
Contribution by Elmira Kotscheva
Во времена отчаяния - отчаянные меры.
I would not clearly classify this Russian phrase in a proverb, but it is a popular phrase and has such advantageous features that it is 1) concise 2) rhithmically sounds and the last but not the least, it renders completely the English saying.
Contribution by Silchenko Victoria
Slovak translation / slovenčina preklad
Zúfale časy si žiadajú zúfale činy.
Contribution by Mariana Sekeráková
Spanish translation / traducción española
A grandes males, grandes remedios.
Ukrainian translation / Український переклад
хіба цикута допомогти й зможе.
A fun booksy variance in Ukrainian (eventually some author's invention, "nomading" between printed editions reimagines the content. Here the sophisticated mental process will be applied as the formal traslation gives us "perhaps the water hemlock {as the last and dangerous resort] could serve in remedy for instance".
Contribution by Silchenko Victoria
Клин клина вибиває. / Від чого захворів, тим і лікуйся.
Contribution by Vatslav