Grapes, raisins, currants and sultanas
These fruits can produce toxicities in dogs, and possibly cats no matter whether they are raw, dried, or cooked. The chance of toxicity is a toss of the coin with some animals ingesting large quantities with no untoward effect, while others ingest only small amounts and develop renal failure. Animals treated symptomatically within hours of ingesting the grapes/raisins have a good prognosis while animals presenting with clinical or biochemical evidence of renal failure have a poor prognosis. If renal failure has not developed within three days of ingestion, then it is unlikely to do so. There is no test available to detect the toxin.
Chocolate
Chocolate toxicity readily occurs in dogs ingesting sometimes even small amounts, particularly if the chocolate is the dark variety. Restlessness and vomiting may progress to agitation, tremors, cardiac arrhythmias and sometimes coma and death. Routine haematology and biochemistry show non-specific changes, and a diagnosis of chocolate/cocoa toxicity is usually based on history and clinical signs. Urine or serum can be submitted for theobromine analysis if there is any question about the diagnosis.
Alliums (onions, leeks, garlic, shallots, chives)
Raw and cooked alliums and their powders contain compounds that damage RBCs resulting in formation of Heinz bodies and eccentrocytes leading to haemolysis and anaemia. Met-haemoglobulin which reduces tissue oxygen delivery may also form. The type and amount of allium eaten determines whether toxicity will occur. In some cases, no clinical signs are seen, however, in severe cases weakness, rapid breathing, staggering and collapse may develop. While cats are more sensitive to allium toxicity, it is more common in dogs, presumably because they are less discriminate in their eating habits.
Macadamia Nuts
Ingestion of macadamia nuts may cause gastrointestinal and or neurological signs in dogs. The signs may develop as soon as 3 hours after ingestion and have typically worn off after about 2 days.