This article is a travel topic
Wikitravel articles have a stay safe section with location specific advice. This article contains general information relevant to many destinations.
Aggressive dogs are a common problem when travelling in places such as Asia, South America and some Eastern European countries like Romania. The dogs are often feral (and hence not used taking commands from people) and may be running round wild in packs, which can be extremely intimidating if you are confronted by one. The obvious precautions — travel in groups, avoid areas where the dogs are, don't go out at night when they are most active, and carry a walking stick if you must go — will reduce the risks but not eliminate them.
Such dogs are rarely rabid, but it is possible. Consider being vaccinated against rabies before travelling to such areas. See individual articles here for region-specific information and consult a physician (preferably one with expertise in travel medicine) for advice on vaccinations before you travel.
What to do when confronted by an aggressive dog
Vinegar spray comes in most handy. Advisable to prepare sling type holder to carry it around without hassles.
Advantages of vinegar spray: 1-Extremely cheap & easy to use for anyone.
2-So effective striking dogs' sense of smell 50000 times keener than man. And vinegar is one of the things what they hate worst.
3-Easy replenishment after use. Juice of Lemon or lime can substitute vinegar).
4-High portability. Unlike compressed aerosol spray, it does not have to be put in your check-in baggage. You can carry it in your in cabin baggage with you(take them down before you enter airport and plane). Vinegar to be kept in a small screw top bottle less than 100cc to comply with the air traffic laws.
5-Consistent power of propellent. As the nature of manually operated spray, it can always maintain the same level of pressure to discharge the fluid. So whatever number of rounds you shoot, the range will never be any shorter.
Remember: 1-Dry fire 4-5 times to be ready to shoot immediately. In other words, the inner syphon must be filled up with vinegar to get ready.
2-Practice well enough before you use it against violent dogs. Your training will better your skill, calmness, and readiness in a critical moment of confrontation. Dogs are known to sense man's fear. So your confidence will be one additional invisible force against them.
3-3 shots are better than one. When you shoot to defend yourself, pump a few rounds at a time instead of just one. This way, they will be truly stunned. And they usually start to avoid you ever after. You will be recognized as the wrong person to aggress.
What to do if you're attacked
If you're unlucky enough to get attacked, there are a number of things you can do to minimize the damage.