Common side effects of Doxycycline Hyclate may include: * Diarrhea * Nausea * Vomiting * Stomach pain * Increased sun sensitivity * Changes in pigmentation (such as darkening of the skin, scars, and other areas) * Mild headaches * Fatigue Serious side effects can also occur. If you experience any of these symptoms, stop taking Doxycycline Hyclate and seek medical attention immediately: * Swelling of the face, lips, tongue, or throat * Severe stomach pain or bloody diarrhea * A fever that does not go away * Yellowing of the skin or eyes (jaundice) Doxycycline Hyclate Contraindications: There are several contraindications to consider before taking Doxycycline Hyclate. If you have any of the following conditions, you should not take this medication without consulting your healthcare provider first: * Allergy to doxycycline or other tetracyclines * A history of gastrointestinal disease, such as inflammatory bowel disease or ulcerative colitis * Pregnancy or breastfeeding * Children under the age of 8 * Photosensitive conditions, such as lupus or porphyria Conclusion: Doxycycline Hyclate is an effective antibiotic that can be purchased at Walmart and other pharmacies without a prescription. However, it's important to be aware of potential side effects and contraindications before taking this medication. If you have any questions or concerns, be sure to discuss them with your healthcare provider.