Urine with bad smell and foul smell may be a sign of bacteria or dehydration due to poor water intake.
A high concentration of urea leaves the urine with bad smell and strong odor. Usually this occurs when the urine is poorly diluted due to dehydration, which is easily noticed in its color, which turns yellow strong or even brown.
If the urine is well diluted, ie with a light yellow or colorless color, but still have a strong odor, may be indicative of the presence of bacteria that metabolize ammonia.
Infections of the urethra can also cause bad smell in the urine, especially if it comes with a urethral discharge. Some medicines and foods alter the color and odor of urine.
Does antibiotic change the color and smell of urine and faeces?
Dark urine: what can it be?
Very yellow urine: what can it be?
After increasing the water intake (at least 2 liters / day) and continuing with bad smell in the urine, it is best to seek a general practitioner or family physician for research.