Background: Although the stress response can enhance the probability of survival in the face of true environmental threats, repeated activation in response to frequent or chronic stress can have serious pathological sequelae. Objective:  This work was carried out to investigate the effect of crowding or noise stresses on some biochemical parameters and histological structure of the liver and kidney tissues of adult male albino rats after one month from chronic exposure to these environmental stressors.  Material and Methods: Crowding was induced by multiplying the normal density by three. Noise was prepared by using 5 different sources of no harmonic sounds and high intensity music. Animals were divided into three equal groups:

Control group.
Rats exposed to noise for 30 days (over 90db, 4h/day).
Rats exposed to crowding for 30 days.

At the end of experiment, blood samples were obtained for determination of:
1- Blood glucose.
2- Lipid profile (total cholesterol, TGs, HDL and LDL).
3- Liver functions tests (AST, ALT, total serum protein, serum albumin and serum bilirubin).
4- Kidney functions tests (blood urea, serum creatinine and uric acid).
Results: Both noise and crowding had similar effects on different measured parameters:

A significant increase in blood glucose, total cholesterol, TGs, LDL, AST, ALT, total serum protein and serum creatinine.
A significant decrease in serum albumin.

Exposure to crowding and noise led to many pathological changes in the liver tissues of rats. These changes included dilated congested central vein with irregular wall, vacuolated hepatocytes with destructive nuclei, increased numbers of von Kupffer cells and lymphocytic infiltration. Exposure of rats to crowding and noise showed several dystrophic changes in the kidney tissue. These changes included: highly atrophied glomeruli, faintly stained cells and nuclei of the convoluted tubules with wide lamina of the distal ones, ruptured brush borders of the proximal ones, thickened arterial walls with branched and corrugated walls of the congested vein.
Conclusion: Exposure to noise or crowding stressors showed many disturbances in liver and kidney parameters.