Kambo triggers a rapid detoxification process, which can be experienced as sensations of warmth, increased sweating, increased circulation and hightened cleansing mechanisms of the body. Rising nausea will in most treatments result in purging of toxins through either puking or visiting the toilet. Puking from kambo is different from puking during alcohol or food poisoning. The kambo purge contains mostly water and is therefore more comfortable.
The effects of kambo are attributed to bio–active constituents called peptides, which trigger various processes in the body, including increased heart rate and blood pressure. A family of peptides called Phyllomedusins has shown to have a potent effect on secretion and contraction of the smooth muscles in the digestive system and is believed to be the main cause behind puking from this medicine.
You can read more about peptides in the science-section.
Psychological and emotional effects
Observation shows that those who take kambo generally get ill less often, have more energy, experience less pain, handle stress easier and are more emotionally robust. Other benefits observed include increased mental focus, general well being, support in overcoming depression and the ability to let go of traumas.   
Kambo has shown to be effective in the treatment of anxiety, depression, PTSD, CFS, chronic pain, HIV, arthritis, diabetes, candida, herpes, high blood pressure, cancer, lyme disease, fertility issues, ongoing infections and more. Individuals with these conditions can experience benefits from specifically tailored kambo treatments.   
1. Kambo the spirit of the shaman – Marcelo Bolshaw Gomes, Professor of Sociology of Comunication UFRN (Federal University of Rio Grande do Norte, Natal (15.07.2009) http://www.ayahuasca.com/psyche/kambo-the-spirit-of-the-shaman/
2. Kambo Natures vaccine for the mind and body – Intervju med Karen Kanya-Darke (4.09.2015)
3. Pharmacological studies of ‘sapo’ from the frog Phyllomedusa bicolor skin: a drug used by the Peruvian Matses Indians in shamanic hunting practices. (31. 09. 1993) https://www.ncbi.nlm.nih.gov/pubmed/8266343
4. Potential therapeutic application of multifunctional host-defense peptides from frog skin as anti-cancer, anti-viral, immunomodulatory, and anti-diabetic agents (02. 05. 2014) https://www.ncbi.nlm.nih.gov/pubmed/24793775
5. Phyllomedusa bicolor skin secretion and the kambô ritual (02. 09. 2014) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4582952/