Can onions and Chinese dates (red dates) be eaten together?
Generally speaking, onions and red dates can be consumed together, but in moderation. The detailed explanation is as follows:

Prostaglandins and sulfides in onions can reduce blood viscosity, dilate blood vessels, and relieve vascular pressure. The cyclic adenosine monophosphate (cAMP) in red dates enhances myocardial contractility and improves microcirculation. Combined, these two ingredients help protect cardiovascular and cerebrovascular health. The vitamin C and trace elements found in both onions and red dates can help eliminate free radicals in the body and enhance skin cell metabolism, thereby promoting skin health and beauty.
Onions and red dates can stimulate secretion of digestive juices, aid digestion, and alleviate symptoms such as abdominal distension and indigestion caused by weak spleen and stomach function. They also have the effect of inducing perspiration and relieving superficial symptoms, so moderate consumption during autumn and winter may help prevent colds caused by exposure to cold. However, it is important to consume them in moderation, as both onions and red dates contain certain amounts of sugar and dietary fiber, excessive intake of which may cause bloating, acid reflux, or fluctuations in blood sugar levels.
People suffering from gastrointestinal diseases such as gastritis or peptic ulcers should avoid consuming excessive amounts of onions and red dates to prevent worsening of their conditions. Due to their high sugar content, intake of red dates should be controlled, and they should be consumed together with protein or healthy fats to delay the rise in blood sugar levels.