1. A pharmaceutical composition comprising viable lactobacilli bacteria and a pharmaceutically acceptable delivery vehicle for the micro-encapsulated bacteria, said delivery vehicle including a pharmaceutically acceptable excipient, wherein a unit dose thereof comprises at least approximately 10<3> viable lactobacilli bacteria, said bacteria being micro-encapsulated whereby the bacteria stay viable during storage of the composition, the substance providing the encapsulating coating for the bacteria being such that it releases bacteria upon prolonged exposure to moisture. 2. The pharmaceutical composition of Claim 1 comprising in a unit dose thereof at least approximately 10<5> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 3. The pharmaceutical composition of Claim 1 wherein the bacteria are of the lactobacillus rhamnosus variant. 4. The pharmaceutical composition of Claim 1 wherein the delivery vehicle is adapted for oral delivery of the micro-encapsulated bacteria to a human patient. 5. The pharmaceutical composition of Claim 4 wherein the delivery vehicle comprises a gelatin capsule. 6. The pharmaceutical composition of Claim 5 comprising in one capsule at least approximately 10<5> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 7. The pharmaceutical composition of Claim 1 wherein the delivery vehicle is adapted for topical delivery of the micro-encapsulated bacteria to the skin of a human patient. 8. The pharmaceutical composition of Claim 7 wherein 1 gram and 1 milliliter of the composition each comprise at least approximately 10<6> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 9. The pharmaceutical composition of Claim 8 wherein the pharmaceutically acceptable excipient is a powder. 10. The pharmaceutical composition of Claim 1 wherein the delivery vehicle is adapted for intra-vaginal delivery of the micro-encapsulated bacteria to a human patient. 11. The pharmaceutical composition of Claim 10 comprising a vaginal suppository. 12. The pharmaceutical composition of Claim 11 wherein each suppository comprises at least approximately 10<6> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 13. A pharmaceutical composition, comprising viable lactobacilli bacteria and a pharmaceutically acceptable delivery vehicle for the micro-encapsulated bacteria adapted for oral delivery to a human patient, wherein in a unit dose thereof at least approximately 10<3> viable lactobacilli bacteria, said bacteria being micro-encapsulated whereby the bacteria stay viable during storage of the composition, the substance providing the encapsulating coating for the bacteria being such that it releases bacteria upon prolonged exposure to moisture and primarily in the lower intestines. 14. The pharmaceutical composition of Claim 13 wherein a unit dose of the composition is a gelatin capsule. 15. The pharmaceutical composition of Claim 14 wherein the gelatin capsule comprises at least approximately 10<5> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 16. A pharmaceutical composition adapted for topical delivery to the skin of a human patient, comprising in a unit dose thereof at least approximately 10<3> viable lactobacilli bacteria, said bacteria being micro-encapsulated whereby the bacteria stay viable during storage of the composition, the substance providing the encapsulating coating for the bacteria being such that it releases bacteria upon prolonged exposure to moisture. 17. The pharmaceutical composition of Claim 16 wherein 1 gram and 1 milliliter of the composition each comprise at least approximately 10<6> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 18. A pharmaceutical composition adapted for intra-vaginal delivery to a human patient, comprising in a unit dose thereof at least approximately 10<3> viable lactobacilli bacteria, said bacteria being micro-encapsulated whereby the bacteria stay viable during storage of the composition, the substance providing the encapsulating coating for the bacteria being such that it releases bacteria upon prolonged exposure to moisture in the vagina. 19. The pharmaceutical composition of Claim 18 which is a vaginal suppository. 20. The pharmaceutical composition of Claim 19 wherein each suppository comprises at least approximately 10<5> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 21. A method of treating or preventing antibiotic associated or other acute or chronic diarrhea in a mammal, including a human being, by orally administering to said mammal a pharmaceutical composition comprising in a unit dose thereof viable lactobacilli bacteria, said pharmaceutical composition is administered to a mammal according to any of Claims 13-15. 22. The method of Claim 21 wherein the mammal is a human being, and wherein at least approximately 4 X 10<3> viable bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant, are administered daily to the human. 23. The method of Claim 21 wherein the viable micro-encapsulated bacteria are orally administered to the human in a gelatin capsule. 24. The method of Claim 23 wherein each capsule contains at least approximately 10<5> viable micro-encapsulated bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant, and wherein approximately 4 capsules are administered to the human being daily. 25. A method of treating or preventing skin infection in a mammal, including a human being, in an area of the skin where skin infections are recurrent in said mammal, wherein said area is topically administered by a pharmaceutical composition according to any of Claims 16-17. 26. The method of Claim 25 wherein the mammal is a human being and wherein treating or preventing skin infection a unit dose of said composition comprises at least approximately 10<5> viable micro-encapsulated bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 27. The method of Claim 27 wherein the composition comprises a powder. 28. A method of treating or preventing yeast infection in a female mammal, including a female human, by intra-vaginally delivering to said female a pharmaceutical composition according to any of Claims 18-20. 29. The method of Claim 28 wherein the pharmaceutical composition is a vaginal suppository, comprising at least approximately 10<5> viable micro-encapsulated bacteria of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant. 30. Micro-encapsulated lactobacilli bacteria, comprising at least 10<3> viable lactobacilli bacteria, and an encapsulating coating, the substance providing the encapsulating coating for the bacteria being such that it releases bacteria upon prolonged exposure to moisture. 31. The micro-encapsulated lactobacilli bacteria of Claim 30, wherein the bacteria are of the lactobacillus acidophilus species or of its lactobacillus rhamnosus variant.