There is an extremely good reason why bags of calcium oxide/hydroxide have warning labels on them warning against ingestion and contact with skin or other tissues. Even if the hydroxide is buffered with an acid like lemon juice, unless the person has a pH meter on hand there is no way for them to know when enough acid is added to neutralize the caustic hydroxide. It is like playing Russian roulette. You never which time is the one that can cost you your life.

http://www.jtbaker.com/msds/englishhtml/c0407.htm

"Ingestion: Gastric irritant. Ingestion may be followed by severe pain, vomiting, diarrhea, and collapse. If death does not occur in 24 hours, esophageal perforation may occur, as evidenced by fall in blood pressure and severe pain. A narrowing of the esophagus may occur weeks, months, or years after ingestion, making swallowing difficult. "

http://en.wikipedia.org/wiki/Calcium_hydroxide

"Health risks As with many chemicals, exposure may pose health risks:[3] Inhalation: Respiratory tract irritation. Coughing, shortness of breath, chemical bronchitis. Ingestion: Internal bleeding, possible perforation of esophagus, severe pain, vomiting, diarrhea, and collapse. Eyes: severe irritation, pain, ulceration, blindness. Skin: burns, blistering. Chronic Exposure: dermatitis or severe irritation to skin."

http://www.bcm.edu/oto/grand/11_17_05.htm

Caustic Ingestion Carlo Viamonte, M.D. November 17, 2005  

"The common agents that are ingested are generally the common agents that are used for cleaning in the area. In the US, they are liquid products such as Liquid Drano. In India, for example, the common products that are ingested are acid agents because more acids are used in the cleaning solutions there. This is an example of some common cleaning solutions containing strong acids and bases. In the household, you have alkali agents containing sodium hydroxide, potassium hydroxide, calcium hydroxide, in things like Liquid Drano. The common acids that are ingested are sulfuric acid and hydrochloric acid. Bleaches include chloride bleaches, and peroxide bleaches. Mildew removers that are used in bathrooms often contain bleaches. The most common ingestions in the United States, about 60% to 80% of the time, are alkali ingestions. This includes lye, as I previously mentioned, as well as ammonia. With this kind of ingestion you end up with, histologically, a liquefaction necrosis. This also causes denaturing of proteins, saponification of fat, and blood vessel thrombosis. The important thing is that there is very early disintegration of the tissues. This allows for very deep penetration and further damage into the muscle layer and beyond at times. About 30% of children ingesting alkali agents end up with esophageal burns, 80% having high grade II and III that do go on oftentimes to develop strictures. Burns tend to be at anatomically narrowing areas. at the cricopharyngeus, the arch of the aorta, etc. The stomach, interestingly, is spared in 80% of the ingestions. Severity of the injury is determined by the amounts of the agent ingested, and the type of the ingestion. If there is food in the stomach, there tends to be less of a caustic injury because of absorption. The GI transit time is also very important, as well as the presence of reflux. If there is significant reflux, the agent can reflux and cause additional damage in the area that had previously been damaged. This early disintegration of mucosa from alkali agents actually can occur over a three-day period after the ingestion, and about days 7-21 the esophagus wall is weakest. Superficial mucosal burns may tend to heal pretty well without sequelae. Burns that disrupt the submucosal and muscular layers often are complicated by severe mucosal loss. After this, an inflammatory reaction is set up. The body begins to try to heal this area, and fibroblasts move in, laying down collagen matrix. This matrix is pretty haphazard and begins to contract in about three weeks. This irregular collagen matrix allows for adhesive bands to form, and some pseudodiverticula can form between these bands. This process continues until finally there is pretty dense scar in the mucosa and in any of the muscular layers that had been previously damaged by the agents. In general, usually a completely circumferential lesion involving the entire wall leads to significant strictures in a clinical setting."