The hearing, which began in Cologne on Tuesday, centres on five middle-aged men who were prescribed the drug by doctors to ease their condition after all other treatments failed.
Although personal cultivation of cannabis is illegal in Germany, the court will rule on the group's demand to be allowed to grow the plant at home because of the high cost of buying it at pharmacies.
The typical monthly outlay of one of the men was €800-€1000. His income is €1500, a lawyer representing the group said. But the state health insurance system refuses to reimburse the cost, prompting the men to seek a legal exemption to grow their own.
Two of the five suffer from multiple sclerosis and two from unspecified acute pain. The fifth suffers from Attention Deficit and Hyperactivity Disorder (ADHD), for which some pre-clinical studies indicate that cannabis effectively alleviates anxiety, depression, insomnia and mood swings.
Currently, 270 people in Germany hold permits to buy and consume cannabis for medical purposes.
High time for change?
The presiding judge, Andreas Fleischfresser, reiterated at Tuesday's hearing that the law does not prohibit the medical use of cannabis, which is a proven pain reliever.
But neither Germany nor international law has any provision for patients to grow their own plants, he said.
Independent of the court's decision, the final say in the matter will, however, lie with the Federal Institute for Medicine and Medicinal Products in Bonn, which has so far vetoed the move despite at least one earlier court ruling in favour.
The main objection is that home cultivated plants can be of inferior quality and potentially harm the consumer's health.
In the case of one of the five men, officials of the institute said he would need to grow 25 individual plants to gather the 100 grammes of cannabis he consumes each month to ease his pain.
But the man is still insisting he should be allowed to convert one of the two rooms in his apartment to make enough space for the crop.
The plants could be nurtured using grow lamps and other cultivation equipment, which are legally sold in Germany despite the ban on actually using them to grow cannabis.
But as well as citing legislative obstacles, authorities say he would have to keep each plant in a special reinforced safety box as a precaution against theft.
Even if these conditions are observed, no permission to grow the plant has yet been issued, stressed court spokesman Raphael Murmann-Suchan.
In June, a court in Münster ruled that it would be legal to grow plants for personal medication. But this was also ultimately blocked by the Bonn institute.
The Cologne court is due to announce its ruling on July 22nd.
The case has also stirred a fresh swell of arguments for and against broader legalization of the soft drug, which is widely used in Germany for recreational purposes.
"When will this ridiculous, manipulated debate finally end? These are just plants," one reader commented on a report of the court case published by the Westdeutsche Allgemeine Zeitung.
Others predicted authorities would never yield in the medicinal sphere because of pressure from the pharmaceutical industry. And some said the ban should never be lifted anyway because soft drug use may lead to highly addictive drugs like crystal meth, use of which is rising in Germany.
"Considering how many young people are using [cannabis], there should be moves to impose far greater control," wrote another reader.
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